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[PATCH 1/4] Add REPACK command. 199+ messages / 2 participants [nested] [flat]
* [PATCH 1/4] Add REPACK command. @ 2025-08-11 13:22 Antonin Houska <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Antonin Houska @ 2025-08-11 13:22 UTC (permalink / raw) The existing CLUSTER command as well as VACUUM with the FULL option both reclaim unused space by rewriting table. Now that we want to enhance this functionality (in particular, by adding a new option CONCURRENTLY), we should enhance both commands because they are both implemented by the same function (cluster.c:cluster_rel). However, adding the same option to two different commands is not very user-friendly. Therefore it was decided to create a new command and to declare both CLUSTER command and the FULL option of VACUUM deprecated. Future enhancements to this rewriting code will only affect the new command. Like CLUSTER, the REPACK command reorders the table according to the specified index. Unlike CLUSTER, REPACK does not require the index: if only table is specified, the command acts as VACUUM FULL. As we don't want to remove CLUSTER and VACUUM FULL yet, there are three callers of the cluster_rel() function now: REPACK, CLUSTER and VACUUM FULL. When we need to distinguish who is calling this function (mostly for logging, but also for progress reporting), we can no longer use the OID of the clustering index: both REPACK and VACUUM FULL can pass InvalidOid. Therefore, this patch introduces a new enumeration type ClusterCommand, and adds an argument of this type to the cluster_rel() function and to all the functions that need to distinguish the caller. Like CLUSTER and VACUUM FULL, the REPACK command without arguments processes all the tables on which the current user has the MAINTAIN privilege. A new view pg_stat_progress_repack view is added to monitor the progress of REPACK. Currently it displays the same information as pg_stat_progress_cluster (except that column names might differ), but it'll also display the status of the REPACK CONCURRENTLY command in the future, so the view definitions will eventually diverge. Regarding user documentation, the patch moves the information on clustering from cluster.sgml to the new file repack.sgml. cluster.sgml now contains a link that points to the related section of repack.sgml. A note on deprecation and a link to repack.sgml are added to both cluster.sgml and vacuum.sgml. --- doc/src/sgml/monitoring.sgml | 223 ++++++- doc/src/sgml/ref/allfiles.sgml | 1 + doc/src/sgml/ref/cluster.sgml | 82 +-- doc/src/sgml/ref/repack.sgml | 254 ++++++++ doc/src/sgml/ref/vacuum.sgml | 9 + doc/src/sgml/reference.sgml | 1 + src/backend/access/heap/heapam_handler.c | 32 +- src/backend/catalog/index.c | 2 +- src/backend/catalog/system_views.sql | 26 + src/backend/commands/cluster.c | 717 +++++++++++++++-------- src/backend/commands/vacuum.c | 3 +- src/backend/parser/gram.y | 77 ++- src/backend/tcop/utility.c | 20 +- src/backend/utils/adt/pgstatfuncs.c | 2 + src/bin/psql/tab-complete.in.c | 33 +- src/include/commands/cluster.h | 7 +- src/include/commands/progress.h | 63 +- src/include/nodes/parsenodes.h | 20 +- src/include/parser/kwlist.h | 1 + src/include/tcop/cmdtaglist.h | 1 + src/include/utils/backend_progress.h | 1 + src/test/regress/expected/cluster.out | 125 +++- src/test/regress/expected/rules.out | 23 + src/test/regress/sql/cluster.sql | 59 ++ src/tools/pgindent/typedefs.list | 3 + 25 files changed, 1406 insertions(+), 379 deletions(-) create mode 100644 doc/src/sgml/ref/repack.sgml diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..12e103d319d 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -405,6 +405,14 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry><structname>pg_stat_progress_repack</structname><indexterm><primary>pg_stat_progress_repack</primary></indexterm></entry> + <entry>One row for each backend running + <command>REPACK</command>, showing current progress. See + <xref linkend="repack-progress-reporting"/>. + </entry> + </row> + <row> <entry><structname>pg_stat_progress_basebackup</structname><indexterm><primary>pg_stat_progress_basebackup</primary></indexterm></entry> <entry>One row for each WAL sender process streaming a base backup, @@ -5506,7 +5514,8 @@ FROM pg_stat_get_backend_idset() AS backendid; certain commands during command execution. Currently, the only commands which support progress reporting are <command>ANALYZE</command>, <command>CLUSTER</command>, - <command>CREATE INDEX</command>, <command>VACUUM</command>, + <command>CREATE INDEX</command>, <command>REPACK</command>, + <command>VACUUM</command>, <command>COPY</command>, and <xref linkend="protocol-replication-base-backup"/> (i.e., replication command that <xref linkend="app-pgbasebackup"/> issues to take @@ -5965,6 +5974,218 @@ FROM pg_stat_get_backend_idset() AS backendid; </table> </sect2> + <sect2 id="repack-progress-reporting"> + <title>REPACK Progress Reporting</title> + + <indexterm> + <primary>pg_stat_progress_repack</primary> + </indexterm> + + <para> + Whenever <command>REPACK</command> is running, + the <structname>pg_stat_progress_repack</structname> view will contain a + row for each backend that is currently running the command. The tables + below describe the information that will be reported and provide + information about how to interpret it. + </para> + + <table id="pg-stat-progress-repack-view" xreflabel="pg_stat_progress_repack"> + <title><structname>pg_stat_progress_repack</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of backend. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>datid</structfield> <type>oid</type> + </para> + <para> + OID of the database to which this backend is connected. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>datname</structfield> <type>name</type> + </para> + <para> + Name of the database to which this backend is connected. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>relid</structfield> <type>oid</type> + </para> + <para> + OID of the table being repacked. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>phase</structfield> <type>text</type> + </para> + <para> + Current processing phase. See <xref linkend="repack-phases"/>. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>repack_index_relid</structfield> <type>oid</type> + </para> + <para> + If the table is being scanned using an index, this is the OID of the + index being used; otherwise, it is zero. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>heap_tuples_scanned</structfield> <type>bigint</type> + </para> + <para> + Number of heap tuples scanned. + This counter only advances when the phase is + <literal>seq scanning heap</literal>, + <literal>index scanning heap</literal> + or <literal>writing new heap</literal>. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>heap_tuples_written</structfield> <type>bigint</type> + </para> + <para> + Number of heap tuples written. + This counter only advances when the phase is + <literal>seq scanning heap</literal>, + <literal>index scanning heap</literal> + or <literal>writing new heap</literal>. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>heap_blks_total</structfield> <type>bigint</type> + </para> + <para> + Total number of heap blocks in the table. This number is reported + as of the beginning of <literal>seq scanning heap</literal>. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>heap_blks_scanned</structfield> <type>bigint</type> + </para> + <para> + Number of heap blocks scanned. This counter only advances when the + phase is <literal>seq scanning heap</literal>. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>index_rebuild_count</structfield> <type>bigint</type> + </para> + <para> + Number of indexes rebuilt. This counter only advances when the phase + is <literal>rebuilding index</literal>. + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <table id="repack-phases"> + <title>REPACK Phases</title> + <tgroup cols="2"> + <colspec colname="col1" colwidth="1*"/> + <colspec colname="col2" colwidth="2*"/> + <thead> + <row> + <entry>Phase</entry> + <entry>Description</entry> + </row> + </thead> + + <tbody> + <row> + <entry><literal>initializing</literal></entry> + <entry> + The command is preparing to begin scanning the heap. This phase is + expected to be very brief. + </entry> + </row> + <row> + <entry><literal>seq scanning heap</literal></entry> + <entry> + The command is currently scanning the table using a sequential scan. + </entry> + </row> + <row> + <entry><literal>index scanning heap</literal></entry> + <entry> + <command>REPACK</command> is currently scanning the table using an index scan. + </entry> + </row> + <row> + <entry><literal>sorting tuples</literal></entry> + <entry> + <command>REPACK</command> is currently sorting tuples. + </entry> + </row> + <row> + <entry><literal>writing new heap</literal></entry> + <entry> + <command>REPACK</command> is currently writing the new heap. + </entry> + </row> + <row> + <entry><literal>swapping relation files</literal></entry> + <entry> + The command is currently swapping newly-built files into place. + </entry> + </row> + <row> + <entry><literal>rebuilding index</literal></entry> + <entry> + The command is currently rebuilding an index. + </entry> + </row> + <row> + <entry><literal>performing final cleanup</literal></entry> + <entry> + The command is performing final cleanup. When this phase is + completed, <command>REPACK</command> will end. + </entry> + </row> + </tbody> + </tgroup> + </table> + </sect2> + <sect2 id="copy-progress-reporting"> <title>COPY Progress Reporting</title> diff --git a/doc/src/sgml/ref/allfiles.sgml b/doc/src/sgml/ref/allfiles.sgml index f5be638867a..c0ef654fcb4 100644 --- a/doc/src/sgml/ref/allfiles.sgml +++ b/doc/src/sgml/ref/allfiles.sgml @@ -167,6 +167,7 @@ Complete list of usable sgml source files in this directory. <!ENTITY refreshMaterializedView SYSTEM "refresh_materialized_view.sgml"> <!ENTITY reindex SYSTEM "reindex.sgml"> <!ENTITY releaseSavepoint SYSTEM "release_savepoint.sgml"> +<!ENTITY repack SYSTEM "repack.sgml"> <!ENTITY reset SYSTEM "reset.sgml"> <!ENTITY revoke SYSTEM "revoke.sgml"> <!ENTITY rollback SYSTEM "rollback.sgml"> diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml index 8811f169ea0..ee4fd965928 100644 --- a/doc/src/sgml/ref/cluster.sgml +++ b/doc/src/sgml/ref/cluster.sgml @@ -42,18 +42,6 @@ CLUSTER [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <r <replaceable class="parameter">table_name</replaceable>. </para> - <para> - When a table is clustered, it is physically reordered - based on the index information. Clustering is a one-time operation: - when the table is subsequently updated, the changes are - not clustered. That is, no attempt is made to store new or - updated rows according to their index order. (If one wishes, one can - periodically recluster by issuing the command again. Also, setting - the table's <literal>fillfactor</literal> storage parameter to less than - 100% can aid in preserving cluster ordering during updates, since updated - rows are kept on the same page if enough space is available there.) - </para> - <para> When a table is clustered, <productname>PostgreSQL</productname> remembers which index it was clustered by. The form @@ -78,6 +66,25 @@ CLUSTER [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <r database operations (both reads and writes) from operating on the table until the <command>CLUSTER</command> is finished. </para> + + <warning> + <para> + The <command>CLUSTER</command> command is deprecated in favor of + <xref linkend="sql-repack"/>. + </para> + </warning> + + <note> + <para> + <xref linkend="sql-repack-notes-on-clustering"/> explain how clustering + works, whether it is initiated by <command>CLUSTER</command> or + by <command>REPACK</command>. The notable difference between the two is + that <command>REPACK</command> does not remember the index used last + time. Thus if you don't specify an index, <command>REPACK</command> + rewrites the table but does not try to cluster it. + </para> + </note> + </refsect1> <refsect1> @@ -136,63 +143,12 @@ CLUSTER [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <r on the table. </para> - <para> - In cases where you are accessing single rows randomly - within a table, the actual order of the data in the - table is unimportant. However, if you tend to access some - data more than others, and there is an index that groups - them together, you will benefit from using <command>CLUSTER</command>. - If you are requesting a range of indexed values from a table, or a - single indexed value that has multiple rows that match, - <command>CLUSTER</command> will help because once the index identifies the - table page for the first row that matches, all other rows - that match are probably already on the same table page, - and so you save disk accesses and speed up the query. - </para> - - <para> - <command>CLUSTER</command> can re-sort the table using either an index scan - on the specified index, or (if the index is a b-tree) a sequential - scan followed by sorting. It will attempt to choose the method that - will be faster, based on planner cost parameters and available statistical - information. - </para> - <para> While <command>CLUSTER</command> is running, the <xref linkend="guc-search-path"/> is temporarily changed to <literal>pg_catalog, pg_temp</literal>. </para> - <para> - When an index scan is used, a temporary copy of the table is created that - contains the table data in the index order. Temporary copies of each - index on the table are created as well. Therefore, you need free space on - disk at least equal to the sum of the table size and the index sizes. - </para> - - <para> - When a sequential scan and sort is used, a temporary sort file is - also created, so that the peak temporary space requirement is as much - as double the table size, plus the index sizes. This method is often - faster than the index scan method, but if the disk space requirement is - intolerable, you can disable this choice by temporarily setting <xref - linkend="guc-enable-sort"/> to <literal>off</literal>. - </para> - - <para> - It is advisable to set <xref linkend="guc-maintenance-work-mem"/> to - a reasonably large value (but not more than the amount of RAM you can - dedicate to the <command>CLUSTER</command> operation) before clustering. - </para> - - <para> - Because the planner records statistics about the ordering of - tables, it is advisable to run <link linkend="sql-analyze"><command>ANALYZE</command></link> - on the newly clustered table. - Otherwise, the planner might make poor choices of query plans. - </para> - <para> Because <command>CLUSTER</command> remembers which indexes are clustered, one can cluster the tables one wants clustered manually the first time, diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml new file mode 100644 index 00000000000..a612c72d971 --- /dev/null +++ b/doc/src/sgml/ref/repack.sgml @@ -0,0 +1,254 @@ +<!-- +doc/src/sgml/ref/repack.sgml +PostgreSQL documentation +--> + +<refentry id="sql-repack"> + <indexterm zone="sql-repack"> + <primary>REPACK</primary> + </indexterm> + + <refmeta> + <refentrytitle>REPACK</refentrytitle> + <manvolnum>7</manvolnum> + <refmiscinfo>SQL - Language Statements</refmiscinfo> + </refmeta> + + <refnamediv> + <refname>REPACK</refname> + <refpurpose>rewrite a table to reclaim disk space</refpurpose> + </refnamediv> + + <refsynopsisdiv> +<synopsis> +REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <replaceable class="parameter">table_name</replaceable> [ USING INDEX <replaceable class="parameter">index_name</replaceable> ] ] + +<phrase>where <replaceable class="parameter">option</replaceable> can be one of:</phrase> + + VERBOSE [ <replaceable class="parameter">boolean</replaceable> ] +</synopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para> + <command>REPACK</command> reclaims storage occupied by dead + tuples. Unlike <command>VACUUM</command>, it does so by rewriting the + entire contents of the table specified + by <replaceable class="parameter">table_name</replaceable> into a new disk + file with no extra space (except for the space guaranteed by + the <literal>fillfactor</literal> storage parameter), allowing unused space + to be returned to the operating system. + </para> + + <para> + Without + a <replaceable class="parameter">table_name</replaceable>, <command>REPACK</command> + processes every table and materialized view in the current database that + the current user has the <literal>MAINTAIN</literal> privilege on. This + form of <command>REPACK</command> cannot be executed inside a transaction + block. + </para> + + <para> + If <replaceable class="parameter">index_name</replaceable> is specified, + the table is clustered by this index. Please see the notes on clustering + below. + </para> + + <para> + When a table is being repacked, an <literal>ACCESS EXCLUSIVE</literal> lock + is acquired on it. This prevents any other database operations (both reads + and writes) from operating on the table until the <command>REPACK</command> + is finished. + </para> + + <refsect2 id="sql-repack-notes-on-clustering" xreflabel="Notes on Clustering"> + <title>Notes on Clustering</title> + + <para> + When a table is clustered, it is physically reordered based on the index + information. Clustering is a one-time operation: when the table is + subsequently updated, the changes are not clustered. That is, no attempt + is made to store new or updated rows according to their index order. (If + one wishes, one can periodically recluster by issuing the command again. + Also, setting the table's <literal>fillfactor</literal> storage parameter + to less than 100% can aid in preserving cluster ordering during updates, + since updated rows are kept on the same page if enough space is available + there.) + </para> + + <para> + In cases where you are accessing single rows randomly within a table, the + actual order of the data in the table is unimportant. However, if you tend + to access some data more than others, and there is an index that groups + them together, you will benefit from using <command>REPACK</command>. If + you are requesting a range of indexed values from a table, or a single + indexed value that has multiple rows that match, + <command>REPACK</command> will help because once the index identifies the + table page for the first row that matches, all other rows that match are + probably already on the same table page, and so you save disk accesses and + speed up the query. + </para> + + <para> + <command>REPACK</command> can re-sort the table using either an index scan + on the specified index (if the index is a b-tree), or a sequential scan + followed by sorting. It will attempt to choose the method that will be + faster, based on planner cost parameters and available statistical + information. + </para> + + <para> + Because the planner records statistics about the ordering of tables, it is + advisable to + run <link linkend="sql-analyze"><command>ANALYZE</command></link> on the + newly repacked table. Otherwise, the planner might make poor choices of + query plans. + </para> + </refsect2> + + <refsect2 id="sql-repack-notes-on-resources" xreflabel="Notes on Resources"> + <title>Notes on Resources</title> + + <para> + When an index scan or a sequential scan without sort is used, a temporary + copy of the table is created that contains the table data in the index + order. Temporary copies of each index on the table are created as well. + Therefore, you need free space on disk at least equal to the sum of the + table size and the index sizes. + </para> + + <para> + When a sequential scan and sort is used, a temporary sort file is also + created, so that the peak temporary space requirement is as much as double + the table size, plus the index sizes. This method is often faster than + the index scan method, but if the disk space requirement is intolerable, + you can disable this choice by temporarily setting + <xref linkend="guc-enable-sort"/> to <literal>off</literal>. + </para> + + <para> + It is advisable to set <xref linkend="guc-maintenance-work-mem"/> to a + reasonably large value (but not more than the amount of RAM you can + dedicate to the <command>REPACK</command> operation) before repacking. + </para> + </refsect2> + + </refsect1> + + <refsect1> + <title>Parameters</title> + + <variablelist> + <varlistentry> + <term><replaceable class="parameter">table_name</replaceable></term> + <listitem> + <para> + The name (possibly schema-qualified) of a table. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">index_name</replaceable></term> + <listitem> + <para> + The name of an index. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>VERBOSE</literal></term> + <listitem> + <para> + Prints a progress report as each table is repacked + at <literal>INFO</literal> level. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">boolean</replaceable></term> + <listitem> + <para> + Specifies whether the selected option should be turned on or off. + You can write <literal>TRUE</literal>, <literal>ON</literal>, or + <literal>1</literal> to enable the option, and <literal>FALSE</literal>, + <literal>OFF</literal>, or <literal>0</literal> to disable it. The + <replaceable class="parameter">boolean</replaceable> value can also + be omitted, in which case <literal>TRUE</literal> is assumed. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Notes</title> + + <para> + To repack a table, one must have the <literal>MAINTAIN</literal> privilege + on the table. + </para> + + <para> + While <command>REPACK</command> is running, the <xref + linkend="guc-search-path"/> is temporarily changed to <literal>pg_catalog, + pg_temp</literal>. + </para> + + <para> + Each backend running <command>REPACK</command> will report its progress + in the <structname>pg_stat_progress_repack</structname> view. See + <xref linkend="repack-progress-reporting"/> for details. + </para> + + <para> + Repacking a partitioned table repacks each of its partitions. If an index + is specified, each partition is repacked using the partition of that + index. <command>REPACK</command> on a partitioned table cannot be executed + inside a transaction block. + </para> + + </refsect1> + + <refsect1> + <title>Examples</title> + + <para> + Repack the table <literal>employees</literal>: +<programlisting> +REPACK employees; +</programlisting> + </para> + + <para> + Repack the table <literal>employees</literal> on the basis of its + index <literal>employees_ind</literal> (Since index is used here, this is + effectively clustering): +<programlisting> +REPACK employees USING INDEX employees_ind; +</programlisting> + </para> + + <para> + Repack all tables in the database on which you have + the <literal>MAINTAIN</literal> privilege: +<programlisting> +REPACK; +</programlisting></para> + </refsect1> + + <refsect1> + <title>Compatibility</title> + + <para> + There is no <command>REPACK</command> statement in the SQL standard. + </para> + + </refsect1> + +</refentry> diff --git a/doc/src/sgml/ref/vacuum.sgml b/doc/src/sgml/ref/vacuum.sgml index bd5dcaf86a5..cee1cf3926c 100644 --- a/doc/src/sgml/ref/vacuum.sgml +++ b/doc/src/sgml/ref/vacuum.sgml @@ -98,6 +98,7 @@ VACUUM [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <re <varlistentry> <term><literal>FULL</literal></term> <listitem> + <para> Selects <quote>full</quote> vacuum, which can reclaim more space, but takes much longer and exclusively locks the table. @@ -106,6 +107,14 @@ VACUUM [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <re the operation is complete. Usually this should only be used when a significant amount of space needs to be reclaimed from within the table. </para> + + <warning> + <para> + The <option>FULL</option> parameter is deprecated in favor of + <xref linkend="sql-repack"/>. + </para> + </warning> + </listitem> </varlistentry> diff --git a/doc/src/sgml/reference.sgml b/doc/src/sgml/reference.sgml index ff85ace83fc..229912d35b7 100644 --- a/doc/src/sgml/reference.sgml +++ b/doc/src/sgml/reference.sgml @@ -195,6 +195,7 @@ &refreshMaterializedView; &reindex; &releaseSavepoint; + &repack; &reset; &revoke; &rollback; diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c index cb4bc35c93e..0b03070d394 100644 --- a/src/backend/access/heap/heapam_handler.c +++ b/src/backend/access/heap/heapam_handler.c @@ -741,13 +741,13 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, if (OldIndex != NULL && !use_sort) { const int ci_index[] = { - PROGRESS_CLUSTER_PHASE, - PROGRESS_CLUSTER_INDEX_RELID + PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_INDEX_RELID }; int64 ci_val[2]; /* Set phase and OIDOldIndex to columns */ - ci_val[0] = PROGRESS_CLUSTER_PHASE_INDEX_SCAN_HEAP; + ci_val[0] = PROGRESS_REPACK_PHASE_INDEX_SCAN_HEAP; ci_val[1] = RelationGetRelid(OldIndex); pgstat_progress_update_multi_param(2, ci_index, ci_val); @@ -759,15 +759,15 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, else { /* In scan-and-sort mode and also VACUUM FULL, set phase */ - pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE, - PROGRESS_CLUSTER_PHASE_SEQ_SCAN_HEAP); + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_SEQ_SCAN_HEAP); tableScan = table_beginscan(OldHeap, SnapshotAny, 0, (ScanKey) NULL); heapScan = (HeapScanDesc) tableScan; indexScan = NULL; /* Set total heap blocks */ - pgstat_progress_update_param(PROGRESS_CLUSTER_TOTAL_HEAP_BLKS, + pgstat_progress_update_param(PROGRESS_REPACK_TOTAL_HEAP_BLKS, heapScan->rs_nblocks); } @@ -809,7 +809,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, * is manually updated to the correct value when the table * scan finishes. */ - pgstat_progress_update_param(PROGRESS_CLUSTER_HEAP_BLKS_SCANNED, + pgstat_progress_update_param(PROGRESS_REPACK_HEAP_BLKS_SCANNED, heapScan->rs_nblocks); break; } @@ -825,7 +825,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, */ if (prev_cblock != heapScan->rs_cblock) { - pgstat_progress_update_param(PROGRESS_CLUSTER_HEAP_BLKS_SCANNED, + pgstat_progress_update_param(PROGRESS_REPACK_HEAP_BLKS_SCANNED, (heapScan->rs_cblock + heapScan->rs_nblocks - heapScan->rs_startblock @@ -912,14 +912,14 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, * In scan-and-sort mode, report increase in number of tuples * scanned */ - pgstat_progress_update_param(PROGRESS_CLUSTER_HEAP_TUPLES_SCANNED, + pgstat_progress_update_param(PROGRESS_REPACK_HEAP_TUPLES_SCANNED, *num_tuples); } else { const int ct_index[] = { - PROGRESS_CLUSTER_HEAP_TUPLES_SCANNED, - PROGRESS_CLUSTER_HEAP_TUPLES_WRITTEN + PROGRESS_REPACK_HEAP_TUPLES_SCANNED, + PROGRESS_REPACK_HEAP_TUPLES_WRITTEN }; int64 ct_val[2]; @@ -952,14 +952,14 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, double n_tuples = 0; /* Report that we are now sorting tuples */ - pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE, - PROGRESS_CLUSTER_PHASE_SORT_TUPLES); + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_SORT_TUPLES); tuplesort_performsort(tuplesort); /* Report that we are now writing new heap */ - pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE, - PROGRESS_CLUSTER_PHASE_WRITE_NEW_HEAP); + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_WRITE_NEW_HEAP); for (;;) { @@ -977,7 +977,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, values, isnull, rwstate); /* Report n_tuples */ - pgstat_progress_update_param(PROGRESS_CLUSTER_HEAP_TUPLES_WRITTEN, + pgstat_progress_update_param(PROGRESS_REPACK_HEAP_TUPLES_WRITTEN, n_tuples); } diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index c4029a4f3d3..3063abff9a5 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -4079,7 +4079,7 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags, Assert(!ReindexIsProcessingIndex(indexOid)); /* Set index rebuild count */ - pgstat_progress_update_param(PROGRESS_CLUSTER_INDEX_REBUILD_COUNT, + pgstat_progress_update_param(PROGRESS_REPACK_INDEX_REBUILD_COUNT, i); i++; } diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..b2b7b10c2be 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -1279,6 +1279,32 @@ CREATE VIEW pg_stat_progress_cluster AS FROM pg_stat_get_progress_info('CLUSTER') AS S LEFT JOIN pg_database D ON S.datid = D.oid; +CREATE VIEW pg_stat_progress_repack AS + SELECT + S.pid AS pid, + S.datid AS datid, + D.datname AS datname, + S.relid AS relid, + -- param1 is currently unused + CASE S.param2 WHEN 0 THEN 'initializing' + WHEN 1 THEN 'seq scanning heap' + WHEN 2 THEN 'index scanning heap' + WHEN 3 THEN 'sorting tuples' + WHEN 4 THEN 'writing new heap' + WHEN 5 THEN 'swapping relation files' + WHEN 6 THEN 'rebuilding index' + WHEN 7 THEN 'performing final cleanup' + END AS phase, + CAST(S.param3 AS oid) AS repack_index_relid, + S.param4 AS heap_tuples_scanned, + S.param5 AS heap_tuples_written, + S.param6 AS heap_blks_total, + S.param7 AS heap_blks_scanned, + S.param8 AS index_rebuild_count + FROM pg_stat_get_progress_info('REPACK') AS S + LEFT JOIN pg_database D ON S.datid = D.oid; + + CREATE VIEW pg_stat_progress_create_index AS SELECT S.pid AS pid, S.datid AS datid, D.datname AS datname, diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index b55221d44cd..af14a230f94 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -67,17 +67,40 @@ typedef struct Oid indexOid; } RelToCluster; - -static void cluster_multiple_rels(List *rtcs, ClusterParams *params); -static void rebuild_relation(Relation OldHeap, Relation index, bool verbose); +static bool cluster_rel_recheck(RepackCommand cmd, Relation OldHeap, + Oid indexOid, Oid userid, int options); +static void rebuild_relation(RepackCommand cmd, bool usingindex, + Relation OldHeap, Relation index, bool verbose); static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, bool verbose, bool *pSwapToastByContent, TransactionId *pFreezeXid, MultiXactId *pCutoffMulti); -static List *get_tables_to_cluster(MemoryContext cluster_context); -static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context, - Oid indexOid); -static bool cluster_is_permitted_for_relation(Oid relid, Oid userid); - +static List *get_tables_to_repack(RepackCommand cmd, bool usingindex, + MemoryContext permcxt); +static List *get_tables_to_repack_partitioned(RepackCommand cmd, + MemoryContext cluster_context, + Oid relid, bool rel_is_index); +static bool cluster_is_permitted_for_relation(RepackCommand cmd, + Oid relid, Oid userid); +static Relation process_single_relation(RepackStmt *stmt, + ClusterParams *params); +static Oid determine_clustered_index(Relation rel, bool usingindex, + const char *indexname); + + +static const char * +RepackCommandAsString(RepackCommand cmd) +{ + switch (cmd) + { + case REPACK_COMMAND_REPACK: + return "REPACK"; + case REPACK_COMMAND_VACUUMFULL: + return "VACUUM"; + case REPACK_COMMAND_CLUSTER: + return "VACUUM"; + } + return "???"; +} /*--------------------------------------------------------------------------- * This cluster code allows for clustering multiple tables at once. Because @@ -104,101 +127,39 @@ static bool cluster_is_permitted_for_relation(Oid relid, Oid userid); *--------------------------------------------------------------------------- */ void -cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel) +ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) { - ListCell *lc; ClusterParams params = {0}; bool verbose = false; Relation rel = NULL; - Oid indexOid = InvalidOid; - MemoryContext cluster_context; + MemoryContext repack_context; List *rtcs; /* Parse option list */ - foreach(lc, stmt->params) + foreach_node(DefElem, opt, stmt->params) { - DefElem *opt = (DefElem *) lfirst(lc); - if (strcmp(opt->defname, "verbose") == 0) verbose = defGetBoolean(opt); else ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), - errmsg("unrecognized CLUSTER option \"%s\"", + errmsg("unrecognized %s option \"%s\"", + RepackCommandAsString(stmt->command), opt->defname), parser_errposition(pstate, opt->location))); } params.options = (verbose ? CLUOPT_VERBOSE : 0); + /* + * If a single relation is specified, process it and we're done ... unless + * the relation is a partitioned table, in which case we fall through. + */ if (stmt->relation != NULL) { - /* This is the single-relation case. */ - Oid tableOid; - - /* - * Find, lock, and check permissions on the table. We obtain - * AccessExclusiveLock right away to avoid lock-upgrade hazard in the - * single-transaction case. - */ - tableOid = RangeVarGetRelidExtended(stmt->relation, - AccessExclusiveLock, - 0, - RangeVarCallbackMaintainsTable, - NULL); - rel = table_open(tableOid, NoLock); - - /* - * Reject clustering a remote temp table ... their local buffer - * manager is not going to cope. - */ - if (RELATION_IS_OTHER_TEMP(rel)) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("cannot cluster temporary tables of other sessions"))); - - if (stmt->indexname == NULL) - { - ListCell *index; - - /* We need to find the index that has indisclustered set. */ - foreach(index, RelationGetIndexList(rel)) - { - indexOid = lfirst_oid(index); - if (get_index_isclustered(indexOid)) - break; - indexOid = InvalidOid; - } - - if (!OidIsValid(indexOid)) - ereport(ERROR, - (errcode(ERRCODE_UNDEFINED_OBJECT), - errmsg("there is no previously clustered index for table \"%s\"", - stmt->relation->relname))); - } - else - { - /* - * The index is expected to be in the same namespace as the - * relation. - */ - indexOid = get_relname_relid(stmt->indexname, - rel->rd_rel->relnamespace); - if (!OidIsValid(indexOid)) - ereport(ERROR, - (errcode(ERRCODE_UNDEFINED_OBJECT), - errmsg("index \"%s\" for table \"%s\" does not exist", - stmt->indexname, stmt->relation->relname))); - } - - /* For non-partitioned tables, do what we came here to do. */ - if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE) - { - cluster_rel(rel, indexOid, ¶ms); - /* cluster_rel closes the relation, but keeps lock */ - + rel = process_single_relation(stmt, ¶ms); + if (rel == NULL) return; - } } /* @@ -207,88 +168,103 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel) * transaction. This forces us to disallow running inside a user * transaction block. */ - PreventInTransactionBlock(isTopLevel, "CLUSTER"); + PreventInTransactionBlock(isTopLevel, RepackCommandAsString(stmt->command)); /* Also, we need a memory context to hold our list of relations */ - cluster_context = AllocSetContextCreate(PortalContext, - "Cluster", - ALLOCSET_DEFAULT_SIZES); + repack_context = AllocSetContextCreate(PortalContext, + "Repack", + ALLOCSET_DEFAULT_SIZES); + + params.options |= CLUOPT_RECHECK; /* - * Either we're processing a partitioned table, or we were not given any - * table name at all. In either case, obtain a list of relations to - * process. - * - * In the former case, an index name must have been given, so we don't - * need to recheck its "indisclustered" bit, but we have to check that it - * is an index that we can cluster on. In the latter case, we set the - * option bit to have indisclustered verified. - * - * Rechecking the relation itself is necessary here in all cases. + * If we don't have a relation yet, determine a relation list. If we do, + * then it must be a partitioned table, and we want to process its + * partitions. */ - params.options |= CLUOPT_RECHECK; - if (rel != NULL) + if (rel == NULL) { - Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE); - check_index_is_clusterable(rel, indexOid, AccessShareLock); - rtcs = get_tables_to_cluster_partitioned(cluster_context, indexOid); - - /* close relation, releasing lock on parent table */ - table_close(rel, AccessExclusiveLock); + Assert(stmt->indexname == NULL); + rtcs = get_tables_to_repack(stmt->command, stmt->usingindex, + repack_context); } else { - rtcs = get_tables_to_cluster(cluster_context); - params.options |= CLUOPT_RECHECK_ISCLUSTERED; - } + Oid relid; + bool rel_is_index; - /* Do the job. */ - cluster_multiple_rels(rtcs, ¶ms); + Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE); - /* Start a new transaction for the cleanup work. */ - StartTransactionCommand(); + /* + * If an index name was specified, resolve it now and pass it down. + */ + if (stmt->usingindex) + { + /* + * XXX how should this behave? Passing no index to a partitioned + * table could be useful to have certain partitions clustered by + * some index, and other partitions by a different index. + */ + if (!stmt->indexname) + ereport(ERROR, + errmsg("there is no previously clustered index for table \"%s\"", + RelationGetRelationName(rel))); - /* Clean up working storage */ - MemoryContextDelete(cluster_context); -} + relid = determine_clustered_index(rel, true, stmt->indexname); + /* XXX is this the right place for this? */ + check_index_is_clusterable(rel, relid, AccessExclusiveLock); + rel_is_index = true; + } + else + { + relid = RelationGetRelid(rel); + rel_is_index = false; + } -/* - * Given a list of relations to cluster, process each of them in a separate - * transaction. - * - * We expect to be in a transaction at start, but there isn't one when we - * return. - */ -static void -cluster_multiple_rels(List *rtcs, ClusterParams *params) -{ - ListCell *lc; + rtcs = get_tables_to_repack_partitioned(stmt->command, repack_context, + relid, rel_is_index); + + /* close parent relation, releasing lock on it */ + table_close(rel, AccessExclusiveLock); + rel = NULL; + } /* Commit to get out of starting transaction */ PopActiveSnapshot(); CommitTransactionCommand(); /* Cluster the tables, each in a separate transaction */ - foreach(lc, rtcs) + Assert(rel == NULL); + foreach_ptr(RelToCluster, rtc, rtcs) { - RelToCluster *rtc = (RelToCluster *) lfirst(lc); - Relation rel; - /* Start a new transaction for each relation. */ StartTransactionCommand(); /* functions in indexes may want a snapshot set */ PushActiveSnapshot(GetTransactionSnapshot()); - rel = table_open(rtc->tableOid, AccessExclusiveLock); + /* + * Open the target table, coping with the case where it has been + * dropped. + */ + rel = try_table_open(rtc->tableOid, AccessExclusiveLock); + if (rel == NULL) + continue; /* Process this table */ - cluster_rel(rel, rtc->indexOid, params); + cluster_rel(stmt->command, stmt->usingindex, + rel, rtc->indexOid, ¶ms); /* cluster_rel closes the relation, but keeps lock */ PopActiveSnapshot(); CommitTransactionCommand(); } + + /* Start a new transaction for the cleanup work. */ + StartTransactionCommand(); + + /* Clean up working storage */ + MemoryContextDelete(repack_context); } /* @@ -304,11 +280,14 @@ cluster_multiple_rels(List *rtcs, ClusterParams *params) * them incrementally while we load the table. * * If indexOid is InvalidOid, the table will be rewritten in physical order - * instead of index order. This is the new implementation of VACUUM FULL, - * and error messages should refer to the operation as VACUUM not CLUSTER. + * instead of index order. + * + * 'cmd' indicates which command is being executed, to be used for error + * messages. */ void -cluster_rel(Relation OldHeap, Oid indexOid, ClusterParams *params) +cluster_rel(RepackCommand cmd, bool usingindex, + Relation OldHeap, Oid indexOid, ClusterParams *params) { Oid tableOid = RelationGetRelid(OldHeap); Oid save_userid; @@ -323,13 +302,25 @@ cluster_rel(Relation OldHeap, Oid indexOid, ClusterParams *params) /* Check for user-requested abort. */ CHECK_FOR_INTERRUPTS(); - pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid); - if (OidIsValid(indexOid)) - pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND, + if (cmd == REPACK_COMMAND_REPACK) + pgstat_progress_start_command(PROGRESS_COMMAND_REPACK, tableOid); + else + pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid); + + if (cmd == REPACK_COMMAND_REPACK) + pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, + PROGRESS_REPACK_COMMAND_REPACK); + else if (cmd == REPACK_COMMAND_CLUSTER) + { + pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, PROGRESS_CLUSTER_COMMAND_CLUSTER); + } else - pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND, + { + Assert(cmd == REPACK_COMMAND_VACUUMFULL); + pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, PROGRESS_CLUSTER_COMMAND_VACUUM_FULL); + } /* * Switch to the table owner's userid, so that any index functions are run @@ -351,63 +342,21 @@ cluster_rel(Relation OldHeap, Oid indexOid, ClusterParams *params) * to cluster a not-previously-clustered index. */ if (recheck) - { - /* Check that the user still has privileges for the relation */ - if (!cluster_is_permitted_for_relation(tableOid, save_userid)) - { - relation_close(OldHeap, AccessExclusiveLock); - goto out; - } - - /* - * Silently skip a temp table for a remote session. Only doing this - * check in the "recheck" case is appropriate (which currently means - * somebody is executing a database-wide CLUSTER or on a partitioned - * table), because there is another check in cluster() which will stop - * any attempt to cluster remote temp tables by name. There is - * another check in cluster_rel which is redundant, but we leave it - * for extra safety. - */ - if (RELATION_IS_OTHER_TEMP(OldHeap)) - { - relation_close(OldHeap, AccessExclusiveLock); + if (!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid, + params->options)) goto out; - } - - if (OidIsValid(indexOid)) - { - /* - * Check that the index still exists - */ - if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(indexOid))) - { - relation_close(OldHeap, AccessExclusiveLock); - goto out; - } - - /* - * Check that the index is still the one with indisclustered set, - * if needed. - */ - if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 && - !get_index_isclustered(indexOid)) - { - relation_close(OldHeap, AccessExclusiveLock); - goto out; - } - } - } /* - * We allow VACUUM FULL, but not CLUSTER, on shared catalogs. CLUSTER - * would work in most respects, but the index would only get marked as - * indisclustered in the current database, leading to unexpected behavior - * if CLUSTER were later invoked in another database. + * We allow repacking shared catalogs only when not using an index. It + * would work to use an index in most respects, but the index would only + * get marked as indisclustered in the current database, leading to + * unexpected behavior if CLUSTER were later invoked in another database. */ - if (OidIsValid(indexOid) && OldHeap->rd_rel->relisshared) + if (usingindex && OldHeap->rd_rel->relisshared) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("cannot cluster a shared catalog"))); + errmsg("cannot run \"%s\" on a shared catalog", + RepackCommandAsString(cmd)))); /* * Don't process temp tables of other backends ... their local buffer @@ -415,21 +364,30 @@ cluster_rel(Relation OldHeap, Oid indexOid, ClusterParams *params) */ if (RELATION_IS_OTHER_TEMP(OldHeap)) { - if (OidIsValid(indexOid)) + if (cmd == REPACK_COMMAND_CLUSTER) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot cluster temporary tables of other sessions"))); + else if (cmd == REPACK_COMMAND_REPACK) + { + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot repack temporary tables of other sessions"))); + } else + { + Assert(cmd == REPACK_COMMAND_VACUUMFULL); ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot vacuum temporary tables of other sessions"))); + } } /* * Also check for active uses of the relation in the current transaction, * including open scans and pending AFTER trigger events. */ - CheckTableNotInUse(OldHeap, OidIsValid(indexOid) ? "CLUSTER" : "VACUUM"); + CheckTableNotInUse(OldHeap, RepackCommandAsString(cmd)); /* Check heap and index are valid to cluster on */ if (OidIsValid(indexOid)) @@ -469,7 +427,7 @@ cluster_rel(Relation OldHeap, Oid indexOid, ClusterParams *params) TransferPredicateLocksToHeapRelation(OldHeap); /* rebuild_relation does all the dirty work */ - rebuild_relation(OldHeap, index, verbose); + rebuild_relation(cmd, usingindex, OldHeap, index, verbose); /* rebuild_relation closes OldHeap, and index if valid */ out: @@ -482,6 +440,63 @@ out: pgstat_progress_end_command(); } +/* + * Check if the table (and its index) still meets the requirements of + * cluster_rel(). + */ +static bool +cluster_rel_recheck(RepackCommand cmd, Relation OldHeap, Oid indexOid, + Oid userid, int options) +{ + Oid tableOid = RelationGetRelid(OldHeap); + + /* Check that the user still has privileges for the relation */ + if (!cluster_is_permitted_for_relation(cmd, tableOid, userid)) + { + relation_close(OldHeap, AccessExclusiveLock); + return false; + } + + /* + * Silently skip a temp table for a remote session. Only doing this check + * in the "recheck" case is appropriate (which currently means somebody is + * executing a database-wide CLUSTER or on a partitioned table), because + * there is another check in cluster() which will stop any attempt to + * cluster remote temp tables by name. There is another check in + * cluster_rel which is redundant, but we leave it for extra safety. + */ + if (RELATION_IS_OTHER_TEMP(OldHeap)) + { + relation_close(OldHeap, AccessExclusiveLock); + return false; + } + + if (OidIsValid(indexOid)) + { + /* + * Check that the index still exists + */ + if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(indexOid))) + { + relation_close(OldHeap, AccessExclusiveLock); + return false; + } + + /* + * Check that the index is still the one with indisclustered set, if + * needed. + */ + if ((options & CLUOPT_RECHECK_ISCLUSTERED) != 0 && + !get_index_isclustered(indexOid)) + { + relation_close(OldHeap, AccessExclusiveLock); + return false; + } + } + + return true; +} + /* * Verify that the specified heap and index are valid to cluster on * @@ -626,7 +641,8 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal) * On exit, they are closed, but locks on them are not released. */ static void -rebuild_relation(Relation OldHeap, Relation index, bool verbose) +rebuild_relation(RepackCommand cmd, bool usingindex, + Relation OldHeap, Relation index, bool verbose) { Oid tableOid = RelationGetRelid(OldHeap); Oid accessMethod = OldHeap->rd_rel->relam; @@ -642,8 +658,8 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose) Assert(CheckRelationLockedByMe(OldHeap, AccessExclusiveLock, false) && (index == NULL || CheckRelationLockedByMe(index, AccessExclusiveLock, false))); - if (index) - /* Mark the correct index as clustered */ + /* for CLUSTER or REPACK USING INDEX, mark the index as the one to use */ + if (usingindex) mark_index_clustered(OldHeap, RelationGetRelid(index), true); /* Remember info about rel before closing OldHeap */ @@ -1458,8 +1474,8 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, int i; /* Report that we are now swapping relation files */ - pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE, - PROGRESS_CLUSTER_PHASE_SWAP_REL_FILES); + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_SWAP_REL_FILES); /* Zero out possible results from swapped_relation_files */ memset(mapped_tables, 0, sizeof(mapped_tables)); @@ -1509,14 +1525,14 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, reindex_flags |= REINDEX_REL_FORCE_INDEXES_PERMANENT; /* Report that we are now reindexing relations */ - pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE, - PROGRESS_CLUSTER_PHASE_REBUILD_INDEX); + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_REBUILD_INDEX); reindex_relation(NULL, OIDOldHeap, reindex_flags, &reindex_params); /* Report that we are now doing clean up */ - pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE, - PROGRESS_CLUSTER_PHASE_FINAL_CLEANUP); + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_FINAL_CLEANUP); /* * If the relation being rebuilt is pg_class, swap_relation_files() @@ -1632,69 +1648,137 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, } } - /* - * Get a list of tables that the current user has privileges on and - * have indisclustered set. Return the list in a List * of RelToCluster - * (stored in the specified memory context), each one giving the tableOid - * and the indexOid on which the table is already clustered. + * Determine which relations to process, when REPACK/CLUSTER is called + * without specifying a table name. The exact process depends on whether + * USING INDEX was given or not, and in any case we only return tables and + * materialized views that the current user has privileges to repack/cluster. + * + * If USING INDEX was given, we scan pg_index to find those that have + * indisclustered set; if it was not given, scan pg_class and return all + * tables. + * + * Return it as a list of RelToCluster in the given memory context. */ static List * -get_tables_to_cluster(MemoryContext cluster_context) +get_tables_to_repack(RepackCommand command, bool usingindex, + MemoryContext permcxt) { - Relation indRelation; + Relation catalog; TableScanDesc scan; - ScanKeyData entry; - HeapTuple indexTuple; - Form_pg_index index; + HeapTuple tuple; MemoryContext old_context; List *rtcs = NIL; - /* - * Get all indexes that have indisclustered set and that the current user - * has the appropriate privileges for. - */ - indRelation = table_open(IndexRelationId, AccessShareLock); - ScanKeyInit(&entry, - Anum_pg_index_indisclustered, - BTEqualStrategyNumber, F_BOOLEQ, - BoolGetDatum(true)); - scan = table_beginscan_catalog(indRelation, 1, &entry); - while ((indexTuple = heap_getnext(scan, ForwardScanDirection)) != NULL) + if (usingindex) { - RelToCluster *rtc; + ScanKeyData entry; + + catalog = table_open(IndexRelationId, AccessShareLock); + ScanKeyInit(&entry, + Anum_pg_index_indisclustered, + BTEqualStrategyNumber, F_BOOLEQ, + BoolGetDatum(true)); + scan = table_beginscan_catalog(catalog, 1, &entry); + while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) + { + RelToCluster *rtc; + Form_pg_index index; - index = (Form_pg_index) GETSTRUCT(indexTuple); + index = (Form_pg_index) GETSTRUCT(tuple); - if (!cluster_is_permitted_for_relation(index->indrelid, GetUserId())) - continue; + /* + * XXX I think the only reason there's no test failure here is + * that we seldom have clustered indexes that would be affected by + * concurrency. Maybe we should also do the + * ConditionalLockRelationOid+SearchSysCacheExists dance that we + * do below. + */ + if (!cluster_is_permitted_for_relation(command, index->indrelid, + GetUserId())) + continue; - /* Use a permanent memory context for the result list */ - old_context = MemoryContextSwitchTo(cluster_context); + /* Use a permanent memory context for the result list */ + old_context = MemoryContextSwitchTo(permcxt); - rtc = (RelToCluster *) palloc(sizeof(RelToCluster)); - rtc->tableOid = index->indrelid; - rtc->indexOid = index->indexrelid; - rtcs = lappend(rtcs, rtc); + rtc = (RelToCluster *) palloc(sizeof(RelToCluster)); + rtc->tableOid = index->indrelid; + rtc->indexOid = index->indexrelid; + rtcs = lappend(rtcs, rtc); - MemoryContextSwitchTo(old_context); + MemoryContextSwitchTo(old_context); + } + } + else + { + catalog = table_open(RelationRelationId, AccessShareLock); + scan = table_beginscan_catalog(catalog, 0, NULL); + + while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) + { + RelToCluster *rtc; + Form_pg_class class; + + class = (Form_pg_class) GETSTRUCT(tuple); + + /* + * Try to obtain a light lock on the table, to ensure it doesn't + * go away while we collect the list. If we cannot, just + * disregard the table. XXX we could release at the bottom of the + * loop, but for now just hold it until this transaction is + * finished. + */ + if (!ConditionalLockRelationOid(class->oid, AccessShareLock)) + continue; + + /* Verify that the table still exists. */ + if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(class->oid))) + { + /* Release useless lock */ + UnlockRelationOid(class->oid, AccessShareLock); + continue; + } + + /* Can only process plain tables and matviews */ + if (class->relkind != RELKIND_RELATION && + class->relkind != RELKIND_MATVIEW) + continue; + + if (!cluster_is_permitted_for_relation(command, class->oid, + GetUserId())) + continue; + + /* Use a permanent memory context for the result list */ + old_context = MemoryContextSwitchTo(permcxt); + + rtc = (RelToCluster *) palloc(sizeof(RelToCluster)); + rtc->tableOid = class->oid; + rtc->indexOid = InvalidOid; + rtcs = lappend(rtcs, rtc); + + MemoryContextSwitchTo(old_context); + } } - table_endscan(scan); - relation_close(indRelation, AccessShareLock); + table_endscan(scan); + relation_close(catalog, AccessShareLock); return rtcs; } /* - * Given an index on a partitioned table, return a list of RelToCluster for + * Given a partitioned table or its index, return a list of RelToCluster for * all the children leaves tables/indexes. * * Like expand_vacuum_rel, but here caller must hold AccessExclusiveLock * on the table containing the index. + * + * 'rel_is_index' tells whether 'relid' is that of an index (true) or of the + * owning relation. */ static List * -get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid) +get_tables_to_repack_partitioned(RepackCommand cmd, MemoryContext cluster_context, + Oid relid, bool rel_is_index) { List *inhoids; ListCell *lc; @@ -1702,17 +1786,33 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid) MemoryContext old_context; /* Do not lock the children until they're processed */ - inhoids = find_all_inheritors(indexOid, NoLock, NULL); + inhoids = find_all_inheritors(relid, NoLock, NULL); foreach(lc, inhoids) { - Oid indexrelid = lfirst_oid(lc); - Oid relid = IndexGetRelation(indexrelid, false); + Oid inhoid = lfirst_oid(lc); + Oid inhrelid, + inhindid; RelToCluster *rtc; - /* consider only leaf indexes */ - if (get_rel_relkind(indexrelid) != RELKIND_INDEX) - continue; + if (rel_is_index) + { + /* consider only leaf indexes */ + if (get_rel_relkind(inhoid) != RELKIND_INDEX) + continue; + + inhrelid = IndexGetRelation(inhoid, false); + inhindid = inhoid; + } + else + { + /* consider only leaf relations */ + if (get_rel_relkind(inhoid) != RELKIND_RELATION) + continue; + + inhrelid = inhoid; + inhindid = InvalidOid; + } /* * It's possible that the user does not have privileges to CLUSTER the @@ -1720,15 +1820,15 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid) * table. We skip any partitions which the user is not permitted to * CLUSTER. */ - if (!cluster_is_permitted_for_relation(relid, GetUserId())) + if (!cluster_is_permitted_for_relation(cmd, inhrelid, GetUserId())) continue; /* Use a permanent memory context for the result list */ old_context = MemoryContextSwitchTo(cluster_context); rtc = (RelToCluster *) palloc(sizeof(RelToCluster)); - rtc->tableOid = relid; - rtc->indexOid = indexrelid; + rtc->tableOid = inhrelid; + rtc->indexOid = inhindid; rtcs = lappend(rtcs, rtc); MemoryContextSwitchTo(old_context); @@ -1742,13 +1842,134 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid) * function emits a WARNING. */ static bool -cluster_is_permitted_for_relation(Oid relid, Oid userid) +cluster_is_permitted_for_relation(RepackCommand cmd, Oid relid, Oid userid) { if (pg_class_aclcheck(relid, userid, ACL_MAINTAIN) == ACLCHECK_OK) return true; + Assert(cmd == REPACK_COMMAND_CLUSTER || cmd == REPACK_COMMAND_REPACK); ereport(WARNING, - (errmsg("permission denied to cluster \"%s\", skipping it", - get_rel_name(relid)))); + errmsg("permission denied to execute %s on \"%s\", skipping it", + cmd == REPACK_COMMAND_CLUSTER ? "CLUSTER" : "REPACK", + get_rel_name(relid))); + return false; } + + +/* + * Given a RepackStmt with an indicated relation name, resolve the relation + * name, obtain lock on it, then determine what to do based on the relation + * type: if it's not a partitioned table, repack it as indicated (using an + * existing clustered index, or following the indicated index), and return + * NULL. + * + * On the other hand, if the table is partitioned, do nothing further and + * instead return the opened relcache entry, so that caller can process the + * partitions using the multiple-table handling code. The index name is not + * resolve in this case. + */ +static Relation +process_single_relation(RepackStmt *stmt, ClusterParams *params) +{ + Relation rel; + Oid tableOid; + + Assert(stmt->relation != NULL); + Assert(stmt->command == REPACK_COMMAND_CLUSTER || + stmt->command == REPACK_COMMAND_REPACK); + + /* + * Find, lock, and check permissions on the table. We obtain + * AccessExclusiveLock right away to avoid lock-upgrade hazard in the + * single-transaction case. + */ + tableOid = RangeVarGetRelidExtended(stmt->relation, + AccessExclusiveLock, + 0, + RangeVarCallbackMaintainsTable, + NULL); + rel = table_open(tableOid, NoLock); + + /* + * Reject clustering a remote temp table ... their local buffer manager is + * not going to cope. + */ + if (RELATION_IS_OTHER_TEMP(rel)) + { + ereport(ERROR, + errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot execute %s on temporary tables of other sessions", + RepackCommandAsString(stmt->command))); + } + + /* + * For partitioned tables, let caller handle this. Otherwise, process it + * here and we're done. + */ + if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) + return rel; + else + { + Oid indexOid; + + indexOid = determine_clustered_index(rel, stmt->usingindex, + stmt->indexname); + check_index_is_clusterable(rel, indexOid, AccessExclusiveLock); + cluster_rel(stmt->command, stmt->usingindex, rel, indexOid, params); + return NULL; + } +} + +/* + * Given a relation and the usingindex/indexname options in a + * REPACK USING INDEX or CLUSTER command, return the OID of the index to use + * for clustering the table. + * + * Caller must hold lock on the relation so that the set of indexes doesn't + * change, and must call check_index_is_clusterable. + */ +static Oid +determine_clustered_index(Relation rel, bool usingindex, const char *indexname) +{ + Oid indexOid; + + if (indexname == NULL && usingindex) + { + ListCell *lc; + + /* Find an index with indisclustered set, or report error */ + foreach(lc, RelationGetIndexList(rel)) + { + indexOid = lfirst_oid(lc); + + if (get_index_isclustered(indexOid)) + break; + indexOid = InvalidOid; + } + + if (!OidIsValid(indexOid)) + ereport(ERROR, + errcode(ERRCODE_UNDEFINED_OBJECT), + errmsg("there is no previously clustered index for table \"%s\"", + RelationGetRelationName(rel))); + } + else if (indexname != NULL) + { + /* + * An index was specified; figure out its name. It must be in the + * same namespace as the relation. + */ + indexOid = get_relname_relid(indexname, + rel->rd_rel->relnamespace); + if (!OidIsValid(indexOid)) + ereport(ERROR, + errcode(ERRCODE_UNDEFINED_OBJECT), + errmsg("index \"%s\" for table \"%s\" does not exist", + indexname, RelationGetRelationName(rel))); + } + else + indexOid = InvalidOid; + + return indexOid; +} diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 733ef40ae7c..8863ad0e8bd 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -2287,7 +2287,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params, cluster_params.options |= CLUOPT_VERBOSE; /* VACUUM FULL is now a variant of CLUSTER; see cluster.c */ - cluster_rel(rel, InvalidOid, &cluster_params); + cluster_rel(REPACK_COMMAND_VACUUMFULL, false, rel, InvalidOid, + &cluster_params); /* cluster_rel closes the relation, but keeps lock */ rel = NULL; diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index db43034b9db..062235817f4 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -280,7 +280,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); AlterCompositeTypeStmt AlterUserMappingStmt AlterRoleStmt AlterRoleSetStmt AlterPolicyStmt AlterStatsStmt AlterDefaultPrivilegesStmt DefACLAction - AnalyzeStmt CallStmt ClosePortalStmt ClusterStmt CommentStmt + AnalyzeStmt CallStmt ClosePortalStmt CommentStmt ConstraintsSetStmt CopyStmt CreateAsStmt CreateCastStmt CreateDomainStmt CreateExtensionStmt CreateGroupStmt CreateOpClassStmt CreateOpFamilyStmt AlterOpFamilyStmt CreatePLangStmt @@ -297,7 +297,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); GrantStmt GrantRoleStmt ImportForeignSchemaStmt IndexStmt InsertStmt ListenStmt LoadStmt LockStmt MergeStmt NotifyStmt ExplainableStmt PreparableStmt CreateFunctionStmt AlterFunctionStmt ReindexStmt RemoveAggrStmt - RemoveFuncStmt RemoveOperStmt RenameStmt ReturnStmt RevokeStmt RevokeRoleStmt + RemoveFuncStmt RemoveOperStmt RenameStmt RepackStmt ReturnStmt RevokeStmt RevokeRoleStmt RuleActionStmt RuleActionStmtOrEmpty RuleStmt SecLabelStmt SelectStmt TransactionStmt TransactionStmtLegacy TruncateStmt UnlistenStmt UpdateStmt VacuumStmt @@ -316,7 +316,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); %type <str> opt_single_name %type <list> opt_qualified_name -%type <boolean> opt_concurrently +%type <boolean> opt_concurrently opt_usingindex %type <dbehavior> opt_drop_behavior %type <list> opt_utility_option_list %type <list> utility_option_list @@ -763,7 +763,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); QUOTE QUOTES RANGE READ REAL REASSIGN RECURSIVE REF_P REFERENCES REFERENCING - REFRESH REINDEX RELATIVE_P RELEASE RENAME REPEATABLE REPLACE REPLICA + REFRESH REINDEX RELATIVE_P RELEASE RENAME REPACK REPEATABLE REPLACE REPLICA RESET RESTART RESTRICT RETURN RETURNING RETURNS REVOKE RIGHT ROLE ROLLBACK ROLLUP ROUTINE ROUTINES ROW ROWS RULE @@ -1025,7 +1025,6 @@ stmt: | CallStmt | CheckPointStmt | ClosePortalStmt - | ClusterStmt | CommentStmt | ConstraintsSetStmt | CopyStmt @@ -1099,6 +1098,7 @@ stmt: | RemoveFuncStmt | RemoveOperStmt | RenameStmt + | RepackStmt | RevokeStmt | RevokeRoleStmt | RuleStmt @@ -1135,6 +1135,11 @@ opt_concurrently: | /*EMPTY*/ { $$ = false; } ; +opt_usingindex: + USING INDEX { $$ = true; } + | /* EMPTY */ { $$ = false; } + ; + opt_drop_behavior: CASCADE { $$ = DROP_CASCADE; } | RESTRICT { $$ = DROP_RESTRICT; } @@ -11912,38 +11917,80 @@ CreateConversionStmt: /***************************************************************************** * * QUERY: + * REPACK [ (options) ] [ <qualified_name> [ USING INDEX <index_name> ] ] + * + * obsolete variants: * CLUSTER (options) [ <qualified_name> [ USING <index_name> ] ] * CLUSTER [VERBOSE] [ <qualified_name> [ USING <index_name> ] ] * CLUSTER [VERBOSE] <index_name> ON <qualified_name> (for pre-8.3) * *****************************************************************************/ -ClusterStmt: - CLUSTER '(' utility_option_list ')' qualified_name cluster_index_specification +RepackStmt: + REPACK opt_utility_option_list qualified_name USING INDEX name + { + RepackStmt *n = makeNode(RepackStmt); + + n->command = REPACK_COMMAND_REPACK; + n->relation = $3; + n->indexname = $6; + n->usingindex = true; + n->params = $2; + $$ = (Node *) n; + } + | REPACK opt_utility_option_list qualified_name opt_usingindex + { + RepackStmt *n = makeNode(RepackStmt); + + n->command = REPACK_COMMAND_REPACK; + n->relation = $3; + n->indexname = NULL; + n->usingindex = $4; + n->params = $2; + $$ = (Node *) n; + } + | REPACK opt_usingindex + { + RepackStmt *n = makeNode(RepackStmt); + + n->command = REPACK_COMMAND_REPACK; + n->relation = NULL; + n->indexname = NULL; + n->usingindex = $2; + n->params = NIL; + $$ = (Node *) n; + } + | CLUSTER '(' utility_option_list ')' qualified_name cluster_index_specification { - ClusterStmt *n = makeNode(ClusterStmt); + RepackStmt *n = makeNode(RepackStmt); + n->command = REPACK_COMMAND_CLUSTER; n->relation = $5; n->indexname = $6; + n->usingindex = true; n->params = $3; $$ = (Node *) n; } | CLUSTER opt_utility_option_list { - ClusterStmt *n = makeNode(ClusterStmt); + RepackStmt *n = makeNode(RepackStmt); + n->command = REPACK_COMMAND_CLUSTER; n->relation = NULL; n->indexname = NULL; + n->usingindex = true; n->params = $2; $$ = (Node *) n; } /* unparenthesized VERBOSE kept for pre-14 compatibility */ | CLUSTER opt_verbose qualified_name cluster_index_specification { - ClusterStmt *n = makeNode(ClusterStmt); + RepackStmt *n = makeNode(RepackStmt); + n->command = REPACK_COMMAND_CLUSTER; n->relation = $3; n->indexname = $4; + n->usingindex = true; if ($2) n->params = list_make1(makeDefElem("verbose", NULL, @2)); $$ = (Node *) n; @@ -11951,20 +11998,24 @@ ClusterStmt: /* unparenthesized VERBOSE kept for pre-17 compatibility */ | CLUSTER VERBOSE { - ClusterStmt *n = makeNode(ClusterStmt); + RepackStmt *n = makeNode(RepackStmt); + n->command = REPACK_COMMAND_CLUSTER; n->relation = NULL; n->indexname = NULL; + n->usingindex = true; n->params = list_make1(makeDefElem("verbose", NULL, @2)); $$ = (Node *) n; } /* kept for pre-8.3 compatibility */ | CLUSTER opt_verbose name ON qualified_name { - ClusterStmt *n = makeNode(ClusterStmt); + RepackStmt *n = makeNode(RepackStmt); + n->command = REPACK_COMMAND_CLUSTER; n->relation = $5; n->indexname = $3; + n->usingindex = true; if ($2) n->params = list_make1(makeDefElem("verbose", NULL, @2)); $$ = (Node *) n; @@ -17960,6 +18011,7 @@ unreserved_keyword: | RELATIVE_P | RELEASE | RENAME + | REPACK | REPEATABLE | REPLACE | REPLICA @@ -18592,6 +18644,7 @@ bare_label_keyword: | RELATIVE_P | RELEASE | RENAME + | REPACK | REPEATABLE | REPLACE | REPLICA diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c index 4f4191b0ea6..8a30e081614 100644 --- a/src/backend/tcop/utility.c +++ b/src/backend/tcop/utility.c @@ -277,9 +277,9 @@ ClassifyUtilityCommandAsReadOnly(Node *parsetree) return COMMAND_OK_IN_RECOVERY | COMMAND_OK_IN_READ_ONLY_TXN; } - case T_ClusterStmt: case T_ReindexStmt: case T_VacuumStmt: + case T_RepackStmt: { /* * These commands write WAL, so they're not strictly @@ -854,14 +854,14 @@ standard_ProcessUtility(PlannedStmt *pstmt, ExecuteCallStmt(castNode(CallStmt, parsetree), params, isAtomicContext, dest); break; - case T_ClusterStmt: - cluster(pstate, (ClusterStmt *) parsetree, isTopLevel); - break; - case T_VacuumStmt: ExecVacuum(pstate, (VacuumStmt *) parsetree, isTopLevel); break; + case T_RepackStmt: + ExecRepack(pstate, (RepackStmt *) parsetree, isTopLevel); + break; + case T_ExplainStmt: ExplainQuery(pstate, (ExplainStmt *) parsetree, params, dest); break; @@ -2850,10 +2850,6 @@ CreateCommandTag(Node *parsetree) tag = CMDTAG_CALL; break; - case T_ClusterStmt: - tag = CMDTAG_CLUSTER; - break; - case T_VacuumStmt: if (((VacuumStmt *) parsetree)->is_vacuumcmd) tag = CMDTAG_VACUUM; @@ -2861,6 +2857,10 @@ CreateCommandTag(Node *parsetree) tag = CMDTAG_ANALYZE; break; + case T_RepackStmt: + tag = CMDTAG_REPACK; + break; + case T_ExplainStmt: tag = CMDTAG_EXPLAIN; break; @@ -3498,7 +3498,7 @@ GetCommandLogLevel(Node *parsetree) lev = LOGSTMT_ALL; break; - case T_ClusterStmt: + case T_RepackStmt: lev = LOGSTMT_DDL; break; diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..a1e10e8c2f6 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -268,6 +268,8 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS) cmdtype = PROGRESS_COMMAND_ANALYZE; else if (pg_strcasecmp(cmd, "CLUSTER") == 0) cmdtype = PROGRESS_COMMAND_CLUSTER; + else if (pg_strcasecmp(cmd, "REPACK") == 0) + cmdtype = PROGRESS_COMMAND_REPACK; else if (pg_strcasecmp(cmd, "CREATE INDEX") == 0) cmdtype = PROGRESS_COMMAND_CREATE_INDEX; else if (pg_strcasecmp(cmd, "BASEBACKUP") == 0) diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c index 1f2ca946fc5..31c1ce5dc09 100644 --- a/src/bin/psql/tab-complete.in.c +++ b/src/bin/psql/tab-complete.in.c @@ -1247,7 +1247,7 @@ static const char *const sql_commands[] = { "DELETE FROM", "DISCARD", "DO", "DROP", "END", "EXECUTE", "EXPLAIN", "FETCH", "GRANT", "IMPORT FOREIGN SCHEMA", "INSERT INTO", "LISTEN", "LOAD", "LOCK", "MERGE INTO", "MOVE", "NOTIFY", "PREPARE", - "REASSIGN", "REFRESH MATERIALIZED VIEW", "REINDEX", "RELEASE", + "REASSIGN", "REFRESH MATERIALIZED VIEW", "REINDEX", "RELEASE", "REPACK", "RESET", "REVOKE", "ROLLBACK", "SAVEPOINT", "SECURITY LABEL", "SELECT", "SET", "SHOW", "START", "TABLE", "TRUNCATE", "UNLISTEN", "UPDATE", "VACUUM", "VALUES", "WITH", @@ -4997,6 +4997,37 @@ match_previous_words(int pattern_id, COMPLETE_WITH_QUERY(Query_for_list_of_tablespaces); } +/* REPACK */ + else if (Matches("REPACK")) + COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_clusterables); + else if (Matches("REPACK", "(*)")) + COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_clusterables); + /* If we have REPACK <sth>, then add "USING INDEX" */ + else if (Matches("REPACK", MatchAnyExcept("("))) + COMPLETE_WITH("USING INDEX"); + /* If we have REPACK (*) <sth>, then add "USING INDEX" */ + else if (Matches("REPACK", "(*)", MatchAny)) + COMPLETE_WITH("USING INDEX"); + /* If we have REPACK <sth> USING, then add the index as well */ + else if (Matches("REPACK", MatchAny, "USING", "INDEX")) + { + set_completion_reference(prev3_wd); + COMPLETE_WITH_SCHEMA_QUERY(Query_for_index_of_table); + } + else if (HeadMatches("REPACK", "(*") && + !HeadMatches("REPACK", "(*)")) + { + /* + * This fires if we're in an unfinished parenthesized option list. + * get_previous_words treats a completed parenthesized option list as + * one word, so the above test is correct. + */ + if (ends_with(prev_wd, '(') || ends_with(prev_wd, ',')) + COMPLETE_WITH("VERBOSE"); + else if (TailMatches("VERBOSE")) + COMPLETE_WITH("ON", "OFF"); + } + /* SECURITY LABEL */ else if (Matches("SECURITY")) COMPLETE_WITH("LABEL"); diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h index 60088a64cbb..7f4138c7b36 100644 --- a/src/include/commands/cluster.h +++ b/src/include/commands/cluster.h @@ -31,8 +31,11 @@ typedef struct ClusterParams bits32 options; /* bitmask of CLUOPT_* */ } ClusterParams; -extern void cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel); -extern void cluster_rel(Relation OldHeap, Oid indexOid, ClusterParams *params); + +extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel); + +extern void cluster_rel(RepackCommand command, bool usingindex, + Relation OldHeap, Oid indexOid, ClusterParams *params); extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid, LOCKMODE lockmode); extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal); diff --git a/src/include/commands/progress.h b/src/include/commands/progress.h index 1cde4bd9bcf..5b6639c114c 100644 --- a/src/include/commands/progress.h +++ b/src/include/commands/progress.h @@ -56,24 +56,51 @@ #define PROGRESS_ANALYZE_PHASE_COMPUTE_EXT_STATS 4 #define PROGRESS_ANALYZE_PHASE_FINALIZE_ANALYZE 5 -/* Progress parameters for cluster */ -#define PROGRESS_CLUSTER_COMMAND 0 -#define PROGRESS_CLUSTER_PHASE 1 -#define PROGRESS_CLUSTER_INDEX_RELID 2 -#define PROGRESS_CLUSTER_HEAP_TUPLES_SCANNED 3 -#define PROGRESS_CLUSTER_HEAP_TUPLES_WRITTEN 4 -#define PROGRESS_CLUSTER_TOTAL_HEAP_BLKS 5 -#define PROGRESS_CLUSTER_HEAP_BLKS_SCANNED 6 -#define PROGRESS_CLUSTER_INDEX_REBUILD_COUNT 7 - -/* Phases of cluster (as advertised via PROGRESS_CLUSTER_PHASE) */ -#define PROGRESS_CLUSTER_PHASE_SEQ_SCAN_HEAP 1 -#define PROGRESS_CLUSTER_PHASE_INDEX_SCAN_HEAP 2 -#define PROGRESS_CLUSTER_PHASE_SORT_TUPLES 3 -#define PROGRESS_CLUSTER_PHASE_WRITE_NEW_HEAP 4 -#define PROGRESS_CLUSTER_PHASE_SWAP_REL_FILES 5 -#define PROGRESS_CLUSTER_PHASE_REBUILD_INDEX 6 -#define PROGRESS_CLUSTER_PHASE_FINAL_CLEANUP 7 +/* + * Progress parameters for REPACK. + * + * Note: Since REPACK shares some code with CLUSTER, these values are also + * used by CLUSTER. (CLUSTER is now deprecated, so it makes little sense to + * introduce a separate set of constants.) + */ +#define PROGRESS_REPACK_COMMAND 0 +#define PROGRESS_REPACK_PHASE 1 +#define PROGRESS_REPACK_INDEX_RELID 2 +#define PROGRESS_REPACK_HEAP_TUPLES_SCANNED 3 +#define PROGRESS_REPACK_HEAP_TUPLES_WRITTEN 4 +#define PROGRESS_REPACK_TOTAL_HEAP_BLKS 5 +#define PROGRESS_REPACK_HEAP_BLKS_SCANNED 6 +#define PROGRESS_REPACK_INDEX_REBUILD_COUNT 7 + +/* + * Phases of repack (as advertised via PROGRESS_REPACK_PHASE). + */ +#define PROGRESS_REPACK_PHASE_SEQ_SCAN_HEAP 1 +#define PROGRESS_REPACK_PHASE_INDEX_SCAN_HEAP 2 +#define PROGRESS_REPACK_PHASE_SORT_TUPLES 3 +#define PROGRESS_REPACK_PHASE_WRITE_NEW_HEAP 4 +#define PROGRESS_REPACK_PHASE_SWAP_REL_FILES 5 +#define PROGRESS_REPACK_PHASE_REBUILD_INDEX 6 +#define PROGRESS_REPACK_PHASE_FINAL_CLEANUP 7 + +/* + * Commands of PROGRESS_REPACK + * + * Currently we only have one command, so the PROGRESS_REPACK_COMMAND + * parameter is not necessary. However it makes cluster.c simpler if we have + * the same set of parameters for CLUSTER and REPACK - see the note on REPACK + * parameters above. + */ +#define PROGRESS_REPACK_COMMAND_REPACK 1 + +/* + * Progress parameters for cluster. + * + * Although we need to report REPACK and CLUSTER in separate views, the + * parameters and phases of CLUSTER are a subset of those of REPACK. Therefore + * we just use the appropriate values defined for REPACK above instead of + * defining a separate set of constants here. + */ /* Commands of PROGRESS_CLUSTER */ #define PROGRESS_CLUSTER_COMMAND_CLUSTER 1 diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 86a236bd58b..fcc25a0c592 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -3949,16 +3949,26 @@ typedef struct AlterSystemStmt } AlterSystemStmt; /* ---------------------- - * Cluster Statement (support pbrown's cluster index implementation) + * Repack Statement * ---------------------- */ -typedef struct ClusterStmt +typedef enum RepackCommand +{ + REPACK_COMMAND_CLUSTER, + REPACK_COMMAND_REPACK, + REPACK_COMMAND_VACUUMFULL, +} RepackCommand; + +typedef struct RepackStmt { NodeTag type; - RangeVar *relation; /* relation being indexed, or NULL if all */ - char *indexname; /* original index defined */ + RepackCommand command; /* type of command being run */ + RangeVar *relation; /* relation being repacked */ + char *indexname; /* order tuples by this index */ + bool usingindex; /* whether USING INDEX is specified */ List *params; /* list of DefElem nodes */ -} ClusterStmt; +} RepackStmt; + /* ---------------------- * Vacuum and Analyze Statements diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h index a4af3f717a1..22559369e2c 100644 --- a/src/include/parser/kwlist.h +++ b/src/include/parser/kwlist.h @@ -374,6 +374,7 @@ PG_KEYWORD("reindex", REINDEX, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("relative", RELATIVE_P, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("release", RELEASE, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("rename", RENAME, UNRESERVED_KEYWORD, BARE_LABEL) +PG_KEYWORD("repack", REPACK, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("repeatable", REPEATABLE, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("replace", REPLACE, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("replica", REPLICA, UNRESERVED_KEYWORD, BARE_LABEL) diff --git a/src/include/tcop/cmdtaglist.h b/src/include/tcop/cmdtaglist.h index d250a714d59..cceb312f2b3 100644 --- a/src/include/tcop/cmdtaglist.h +++ b/src/include/tcop/cmdtaglist.h @@ -196,6 +196,7 @@ PG_CMDTAG(CMDTAG_REASSIGN_OWNED, "REASSIGN OWNED", false, false, false) PG_CMDTAG(CMDTAG_REFRESH_MATERIALIZED_VIEW, "REFRESH MATERIALIZED VIEW", true, false, false) PG_CMDTAG(CMDTAG_REINDEX, "REINDEX", true, false, false) PG_CMDTAG(CMDTAG_RELEASE, "RELEASE", false, false, false) +PG_CMDTAG(CMDTAG_REPACK, "REPACK", false, false, false) PG_CMDTAG(CMDTAG_RESET, "RESET", false, false, false) PG_CMDTAG(CMDTAG_REVOKE, "REVOKE", true, false, false) PG_CMDTAG(CMDTAG_REVOKE_ROLE, "REVOKE ROLE", false, false, false) diff --git a/src/include/utils/backend_progress.h b/src/include/utils/backend_progress.h index dda813ab407..e69e366dcdc 100644 --- a/src/include/utils/backend_progress.h +++ b/src/include/utils/backend_progress.h @@ -28,6 +28,7 @@ typedef enum ProgressCommandType PROGRESS_COMMAND_CREATE_INDEX, PROGRESS_COMMAND_BASEBACKUP, PROGRESS_COMMAND_COPY, + PROGRESS_COMMAND_REPACK, } ProgressCommandType; #define PGSTAT_NUM_PROGRESS_PARAM 20 diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out index 4d40a6809ab..5256628b51d 100644 --- a/src/test/regress/expected/cluster.out +++ b/src/test/regress/expected/cluster.out @@ -254,6 +254,63 @@ ORDER BY 1; clstr_tst_pkey (3 rows) +-- REPACK handles individual tables identically to CLUSTER, but it's worth +-- checking if it handles table hierarchies identically as well. +REPACK clstr_tst USING INDEX clstr_tst_c; +-- Verify that inheritance link still works +INSERT INTO clstr_tst_inh VALUES (0, 100, 'in child table 2'); +SELECT a,b,c,substring(d for 30), length(d) from clstr_tst; + a | b | c | substring | length +----+-----+------------------+--------------------------------+-------- + 10 | 14 | catorce | | + 18 | 5 | cinco | | + 9 | 4 | cuatro | | + 26 | 19 | diecinueve | | + 12 | 18 | dieciocho | | + 30 | 16 | dieciseis | | + 24 | 17 | diecisiete | | + 2 | 10 | diez | | + 23 | 12 | doce | | + 11 | 2 | dos | | + 25 | 9 | nueve | | + 31 | 8 | ocho | | + 1 | 11 | once | | + 28 | 15 | quince | | + 32 | 6 | seis | xyzzyxyzzyxyzzyxyzzyxyzzyxyzzy | 500000 + 29 | 7 | siete | | + 15 | 13 | trece | | + 22 | 30 | treinta | | + 17 | 32 | treinta y dos | | + 3 | 31 | treinta y uno | | + 5 | 3 | tres | | + 20 | 1 | uno | | + 6 | 20 | veinte | | + 14 | 25 | veinticinco | | + 21 | 24 | veinticuatro | | + 4 | 22 | veintidos | | + 19 | 29 | veintinueve | | + 16 | 28 | veintiocho | | + 27 | 26 | veintiseis | | + 13 | 27 | veintisiete | | + 7 | 23 | veintitres | | + 8 | 21 | veintiuno | | + 0 | 100 | in child table | | + 0 | 100 | in child table 2 | | +(34 rows) + +-- Verify that foreign key link still works +INSERT INTO clstr_tst (b, c) VALUES (1111, 'this should fail'); +ERROR: insert or update on table "clstr_tst" violates foreign key constraint "clstr_tst_con" +DETAIL: Key (b)=(1111) is not present in table "clstr_tst_s". +SELECT conname FROM pg_constraint WHERE conrelid = 'clstr_tst'::regclass +ORDER BY 1; + conname +---------------------- + clstr_tst_a_not_null + clstr_tst_con + clstr_tst_pkey +(3 rows) + SELECT relname, relkind, EXISTS(SELECT 1 FROM pg_class WHERE oid = c.reltoastrelid) AS hastoast FROM pg_class c WHERE relname LIKE 'clstr_tst%' ORDER BY relname; @@ -381,6 +438,35 @@ SELECT * FROM clstr_1; 2 (2 rows) +-- REPACK w/o argument performs no ordering, so we can only check which tables +-- have the relfilenode changed. +RESET SESSION AUTHORIZATION; +CREATE TEMP TABLE relnodes_old AS +(SELECT relname, relfilenode +FROM pg_class +WHERE relname IN ('clstr_1', 'clstr_2', 'clstr_3')); +SET SESSION AUTHORIZATION regress_clstr_user; +SET client_min_messages = ERROR; -- order of "skipping" warnings may vary +REPACK; +RESET client_min_messages; +RESET SESSION AUTHORIZATION; +CREATE TEMP TABLE relnodes_new AS +(SELECT relname, relfilenode +FROM pg_class +WHERE relname IN ('clstr_1', 'clstr_2', 'clstr_3')); +-- Do the actual comparison. Unlike CLUSTER, clstr_3 should have been +-- processed because there is nothing like clustering index here. +SELECT o.relname FROM relnodes_old o +JOIN relnodes_new n ON o.relname = n.relname +WHERE o.relfilenode <> n.relfilenode +ORDER BY o.relname; + relname +--------- + clstr_1 + clstr_3 +(2 rows) + +SET SESSION AUTHORIZATION regress_clstr_user; -- Test MVCC-safety of cluster. There isn't much we can do to verify the -- results with a single backend... CREATE TABLE clustertest (key int PRIMARY KEY); @@ -495,6 +581,43 @@ ALTER TABLE clstrpart SET WITHOUT CLUSTER; ERROR: cannot mark index clustered in partitioned table ALTER TABLE clstrpart CLUSTER ON clstrpart_idx; ERROR: cannot mark index clustered in partitioned table +-- Check that REPACK sets new relfilenodes: it should process exactly the same +-- tables as CLUSTER did. +DROP TABLE old_cluster_info; +DROP TABLE new_cluster_info; +CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +REPACK clstrpart USING INDEX clstrpart_idx; +CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C"; + relname | level | relkind | ?column? +-------------+-------+---------+---------- + clstrpart | 0 | p | t + clstrpart1 | 1 | p | t + clstrpart11 | 2 | r | f + clstrpart12 | 2 | p | t + clstrpart2 | 1 | r | f + clstrpart3 | 1 | p | t + clstrpart33 | 2 | r | f +(7 rows) + +-- And finally the same for REPACK w/o index. +DROP TABLE old_cluster_info; +DROP TABLE new_cluster_info; +CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +REPACK clstrpart; +CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C"; + relname | level | relkind | ?column? +-------------+-------+---------+---------- + clstrpart | 0 | p | t + clstrpart1 | 1 | p | t + clstrpart11 | 2 | r | f + clstrpart12 | 2 | p | t + clstrpart2 | 1 | r | f + clstrpart3 | 1 | p | t + clstrpart33 | 2 | r | f +(7 rows) + DROP TABLE clstrpart; -- Ownership of partitions is checked CREATE TABLE ptnowner(i int unique) PARTITION BY LIST (i); @@ -513,7 +636,7 @@ CREATE TEMP TABLE ptnowner_oldnodes AS JOIN pg_class AS c ON c.oid=tree.relid; SET SESSION AUTHORIZATION regress_ptnowner; CLUSTER ptnowner USING ptnowner_i_idx; -WARNING: permission denied to cluster "ptnowner2", skipping it +WARNING: permission denied to execute CLUSTER on "ptnowner2", skipping it RESET SESSION AUTHORIZATION; SELECT a.relname, a.relfilenode=b.relfilenode FROM pg_class a JOIN ptnowner_oldnodes b USING (oid) ORDER BY a.relname COLLATE "C"; diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..3a1d1d28282 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -2071,6 +2071,29 @@ pg_stat_progress_create_index| SELECT s.pid, s.param15 AS partitions_done FROM (pg_stat_get_progress_info('CREATE INDEX'::text) s(pid, datid, relid, param1, param2, param3, param4, param5, param6, param7, param8, param9, param10, param11, param12, param13, param14, param15, param16, param17, param18, param19, param20) LEFT JOIN pg_database d ON ((s.datid = d.oid))); +pg_stat_progress_repack| SELECT s.pid, + s.datid, + d.datname, + s.relid, + CASE s.param2 + WHEN 0 THEN 'initializing'::text + WHEN 1 THEN 'seq scanning heap'::text + WHEN 2 THEN 'index scanning heap'::text + WHEN 3 THEN 'sorting tuples'::text + WHEN 4 THEN 'writing new heap'::text + WHEN 5 THEN 'swapping relation files'::text + WHEN 6 THEN 'rebuilding index'::text + WHEN 7 THEN 'performing final cleanup'::text + ELSE NULL::text + END AS phase, + (s.param3)::oid AS repack_index_relid, + s.param4 AS heap_tuples_scanned, + s.param5 AS heap_tuples_written, + s.param6 AS heap_blks_total, + s.param7 AS heap_blks_scanned, + s.param8 AS index_rebuild_count + FROM (pg_stat_get_progress_info('REPACK'::text) s(pid, datid, relid, param1, param2, param3, param4, param5, param6, param7, param8, param9, param10, param11, param12, param13, param14, param15, param16, param17, param18, param19, param20) + LEFT JOIN pg_database d ON ((s.datid = d.oid))); pg_stat_progress_vacuum| SELECT s.pid, s.datid, d.datname, diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql index b7115f86104..cfcc3dc9761 100644 --- a/src/test/regress/sql/cluster.sql +++ b/src/test/regress/sql/cluster.sql @@ -76,6 +76,19 @@ INSERT INTO clstr_tst (b, c) VALUES (1111, 'this should fail'); SELECT conname FROM pg_constraint WHERE conrelid = 'clstr_tst'::regclass ORDER BY 1; +-- REPACK handles individual tables identically to CLUSTER, but it's worth +-- checking if it handles table hierarchies identically as well. +REPACK clstr_tst USING INDEX clstr_tst_c; + +-- Verify that inheritance link still works +INSERT INTO clstr_tst_inh VALUES (0, 100, 'in child table 2'); +SELECT a,b,c,substring(d for 30), length(d) from clstr_tst; + +-- Verify that foreign key link still works +INSERT INTO clstr_tst (b, c) VALUES (1111, 'this should fail'); + +SELECT conname FROM pg_constraint WHERE conrelid = 'clstr_tst'::regclass +ORDER BY 1; SELECT relname, relkind, EXISTS(SELECT 1 FROM pg_class WHERE oid = c.reltoastrelid) AS hastoast @@ -159,6 +172,34 @@ INSERT INTO clstr_1 VALUES (1); CLUSTER clstr_1; SELECT * FROM clstr_1; +-- REPACK w/o argument performs no ordering, so we can only check which tables +-- have the relfilenode changed. +RESET SESSION AUTHORIZATION; +CREATE TEMP TABLE relnodes_old AS +(SELECT relname, relfilenode +FROM pg_class +WHERE relname IN ('clstr_1', 'clstr_2', 'clstr_3')); + +SET SESSION AUTHORIZATION regress_clstr_user; +SET client_min_messages = ERROR; -- order of "skipping" warnings may vary +REPACK; +RESET client_min_messages; + +RESET SESSION AUTHORIZATION; +CREATE TEMP TABLE relnodes_new AS +(SELECT relname, relfilenode +FROM pg_class +WHERE relname IN ('clstr_1', 'clstr_2', 'clstr_3')); + +-- Do the actual comparison. Unlike CLUSTER, clstr_3 should have been +-- processed because there is nothing like clustering index here. +SELECT o.relname FROM relnodes_old o +JOIN relnodes_new n ON o.relname = n.relname +WHERE o.relfilenode <> n.relfilenode +ORDER BY o.relname; + +SET SESSION AUTHORIZATION regress_clstr_user; + -- Test MVCC-safety of cluster. There isn't much we can do to verify the -- results with a single backend... @@ -229,6 +270,24 @@ SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM o CLUSTER clstrpart; ALTER TABLE clstrpart SET WITHOUT CLUSTER; ALTER TABLE clstrpart CLUSTER ON clstrpart_idx; + +-- Check that REPACK sets new relfilenodes: it should process exactly the same +-- tables as CLUSTER did. +DROP TABLE old_cluster_info; +DROP TABLE new_cluster_info; +CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +REPACK clstrpart USING INDEX clstrpart_idx; +CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C"; + +-- And finally the same for REPACK w/o index. +DROP TABLE old_cluster_info; +DROP TABLE new_cluster_info; +CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +REPACK clstrpart; +CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ; +SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C"; + DROP TABLE clstrpart; -- Ownership of partitions is checked diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index e6f2e93b2d6..24f98ed1e9e 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -425,6 +425,7 @@ ClientCertName ClientConnectionInfo ClientData ClientSocket +ClusterCommand ClonePtrType ClosePortalStmt ClosePtrType @@ -2536,6 +2537,8 @@ ReorderBufferTupleCidKey ReorderBufferUpdateProgressTxnCB ReorderTuple RepOriginId +RepackCommand +RepackStmt ReparameterizeForeignPathByChild_function ReplaceVarsFromTargetList_context ReplaceVarsNoMatchOption -- 2.47.1 --=-=-= Content-Type: text/x-diff Content-Disposition: attachment; filename=v18-0002-Refactor-index_concurrently_create_copy-for-use-with.patch ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v50 8/8] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 78 ++++++++++++------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 6 +- 12 files changed, 96 insertions(+), 46 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fdb77df0fdb..a87626a01b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d6e446d582d..2fc30008f59 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3383,7 +3383,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..1bc7f3f600d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..49fb10df038 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,9 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ +int TotalMaxReplicationSlots = 0; /* sum of both */ /* * Invalidate replication slots that have remained idle longer than this @@ -191,12 +194,14 @@ ReplicationSlotsShmemSize(void) { Size size = 0; - if (max_replication_slots == 0) + TotalMaxReplicationSlots = max_replication_slots + max_repack_replication_slots; + + if (TotalMaxReplicationSlots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(TotalMaxReplicationSlots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +214,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +228,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +378,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +386,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +439,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = repack ? max_replication_slots : 0; + endpoint = repack ? TotalMaxReplicationSlots : max_replication_slots; + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +456,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -548,7 +561,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +589,7 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + TotalMaxReplicationSlots); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,7 +1676,11 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* + * FIXME how to relax this for repack in a way that doesn't mess + * everything up? + */ + if (TotalMaxReplicationSlots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); @@ -2224,7 +2241,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (TotalMaxReplicationSlots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2249,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2354,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2455,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (TotalMaxReplicationSlots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2885,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *slot; @@ -2910,6 +2927,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..cdb4dbd87c9 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < TotalMaxReplicationSlots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < TotalMaxReplicationSlots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index e556b8844d8..8eb251659b0 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 2c5e98d1d4d..9e9a390a01b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..88953576894 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,9 +324,13 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; +/* only for slotfuncs.c, slotsync.c etc */ +extern int TotalMaxReplicationSlots; + /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); extern void ReplicationSlotsShmemInit(void); @@ -334,7 +338,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --brnevsqjnuzpyok4-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v51 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index bec18c44cc8..1424446ba7c 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --r2slln3zpmilwu22 Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v51-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v52 09/10] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 3 +- src/backend/commands/repack_worker.c | 4 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 80 +++++++++++-------- src/backend/replication/slotfuncs.c | 8 +- src/backend/replication/walsender.c | 4 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/slot.h | 3 +- 12 files changed, 93 insertions(+), 48 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 422ba304982..a67dd6b9eb1 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d4c1f0e7652..d932d526235 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,8 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + /* FIXME rename to max_repack_processes? */ + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index ff34e246469..610592a05b0 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -233,8 +233,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index d553bd5dbff..2c6c6773ad2 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -152,6 +152,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -189,14 +191,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -209,7 +212,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -223,7 +226,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -373,6 +376,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -380,10 +384,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -432,12 +437,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -445,7 +454,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -455,7 +466,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -548,7 +560,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -576,7 +588,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -870,7 +883,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1252,7 +1265,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1307,7 +1320,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1374,12 +1387,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1454,11 +1467,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1515,13 +1528,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1618,11 +1631,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1663,10 +1676,12 @@ CheckSlotRequirements(void) * needs the same check. */ - if (max_replication_slots == 0) + /* XXX we should be able to check exactly which type of slot we need */ + if (max_replication_slots + max_repack_replication_slots == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errmsg("replication slots can only be used if \"%s\" > 0 or \"%s\" > 0", + "max_replication_slots", "max_repack_replication_slots"))); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2224,7 +2239,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2232,7 +2247,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2337,7 +2352,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2438,7 +2453,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ @@ -2868,7 +2883,7 @@ RestoreSlotFromDisk(const char *name) errhint("Change \"wal_level\" to be \"replica\" or higher."))); /* nothing can be active yet, don't lock anything */ - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot; @@ -2910,6 +2925,7 @@ RestoreSlotFromDisk(const char *name) break; } + /* XXX might be misleading if the slots previously in use were REPACK. */ if (!restored) ereport(FATAL, (errmsg("too many replication slots active before shutdown"), diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..78dd3c4ea66 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -270,7 +270,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -665,7 +665,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..75ef3419a15 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fc0900efe5f..857be159f5c 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2070,6 +2070,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index c8194c27aa7..9c3c5d16361 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..c316a01a807 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); -- 2.47.3 --gp2pyozrd5pweboh Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v52-0010-CheckLogicalDecodingRequirements-be-specific-abo.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v53 7/7] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 92759f33969..6ba86384312 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3381,7 +3381,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qr3jlalmmcpkiodg-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v54 5/5] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 86 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 ++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 117 insertions(+), 63 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d3fea738ca3..a90d163e416 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4638,6 +4638,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index d1be6c60e88..ec3a2cd441d 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3382,7 +3382,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index c85166ba849..39cbb0252f4 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -223,7 +223,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -232,8 +232,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -244,6 +244,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 09964198550..d83125afd0d 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index dc46a372ead..06efcaa60b2 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -308,6 +308,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -328,6 +329,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -344,7 +346,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..28c89c5e10d 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -425,7 +425,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -814,6 +814,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1691,7 +1692,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 9533515a63b..47679161b67 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -151,6 +151,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -188,14 +190,15 @@ static void SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel); Size ReplicationSlotsShmemSize(void) { + int totalslots = max_replication_slots + max_repack_replication_slots; Size size = 0; - if (max_replication_slots == 0) + if (totalslots == 0) return size; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(totalslots, sizeof(ReplicationSlot))); return size; } @@ -208,7 +211,7 @@ ReplicationSlotsShmemInit(void) { bool found; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; ReplicationSlotCtl = (ReplicationSlotCtlData *) @@ -222,7 +225,7 @@ ReplicationSlotsShmemInit(void) /* First time through, so initialize */ MemSet(ReplicationSlotCtl, 0, ReplicationSlotsShmemSize()); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -372,6 +375,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -379,10 +383,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -431,12 +436,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -444,7 +453,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -454,7 +465,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -547,7 +559,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -575,7 +587,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -869,7 +882,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1251,7 +1264,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1306,7 +1319,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1373,12 +1386,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1453,11 +1466,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1514,13 +1527,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1617,11 +1630,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1655,17 +1668,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2216,7 +2236,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2224,7 +2244,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2329,7 +2349,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2430,7 +2450,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 2bb3f34dc6d..9d7d675fa96 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1220,7 +1220,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1240,7 +1240,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1251,7 +1251,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1309,6 +1309,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1466,7 +1467,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index a315c4ab8ab..bf82b8f6048 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2071,6 +2071,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 6d0337853e0..fb75990609e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 4b4709f6e2c..489af7d8d6c 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,6 +324,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; @@ -334,7 +335,7 @@ extern void ReplicationSlotsShmemInit(void); /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -377,7 +378,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --cdhh4t7ukb6tnjoq-- ^ permalink raw reply [nested|flat] 199+ messages in thread
* [PATCH v56 2/3] Reserve replication slots specifically for REPACK @ 2026-04-01 17:54 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 199+ messages in thread From: Álvaro Herrera @ 2026-04-01 17:54 UTC (permalink / raw) This allows REPACK to not interfere with other operations that use replication slots. This eases configurability. --- doc/src/sgml/config.sgml | 16 ++++ doc/src/sgml/ref/repack.sgml | 6 +- src/backend/commands/repack.c | 2 +- src/backend/commands/repack_worker.c | 7 +- src/backend/replication/logical/launcher.c | 2 +- src/backend/replication/logical/logical.c | 8 +- .../replication/logical/logicalfuncs.c | 2 +- src/backend/replication/logical/slotsync.c | 5 +- src/backend/replication/slot.c | 84 ++++++++++++------- src/backend/replication/slotfuncs.c | 19 +++-- src/backend/replication/walsender.c | 9 +- src/backend/utils/misc/guc_parameters.dat | 8 ++ src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/replication/logical.h | 3 +- src/include/replication/slot.h | 5 +- 15 files changed, 116 insertions(+), 62 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3324d2d3c49..3435732646e 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4639,6 +4639,22 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows </listitem> </varlistentry> + <varlistentry id="guc-max-repack-replication-slots" xreflabel="max_repack_replication_slots"> + <term><varname>max_repack_replication_slots</varname> (<type>integer</type>) + <indexterm> + <primary><varname>max_repack_replication_slots</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Specifies the maximum number of replication slots for use of + the <command>REPACK</command> command. The default is 5. + This parameter can only be set at server start. + </para> + </listitem> + </varlistentry> + + <varlistentry id="guc-max-replication-slots" xreflabel="max_replication_slots"> <term><varname>max_replication_slots</varname> (<type>integer</type>) <indexterm> diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index e993dfb3108..c532a39ee07 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -293,9 +293,9 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] USING <listitem> <para> - The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> - configuration parameter does not allow for creation of an additional - replication slot. + The <link linkend="guc-max-repack-replication-slots"><varname>max_repack_replication_slots</varname></link> + configuration parameter does not allow for the creation of an + additional replication slot. </para> </listitem> </itemizedlist> diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 17b639b3b44..5e97fcf3818 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -3357,7 +3357,7 @@ start_repack_decoding_worker(Oid relid) ereport(ERROR, errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("out of background worker slots"), - errhint("You might need to increase \"%s\".", "max_worker_processes")); + errhint("You might need to increase \"%s\".", "max_repack_replication_slots")); decoding_worker->seg = seg; decoding_worker->error_mqh = mqh; diff --git a/src/backend/commands/repack_worker.c b/src/backend/commands/repack_worker.c index 94d034970b5..ea330310e27 100644 --- a/src/backend/commands/repack_worker.c +++ b/src/backend/commands/repack_worker.c @@ -212,7 +212,7 @@ repack_setup_logical_decoding(Oid relid) * Make sure we can use logical decoding. */ CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(true); /* * A single backend should not execute multiple REPACK commands at a time, @@ -221,8 +221,8 @@ repack_setup_logical_decoding(Oid relid) * RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); - ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, false, - false); + ReplicationSlotCreate(NameStr(slotname), true, RS_TEMPORARY, false, true, + false, false); EnsureLogicalDecodingEnabled(); @@ -233,6 +233,7 @@ repack_setup_logical_decoding(Oid relid) ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, NIL, true, + true, InvalidXLogRecPtr, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c index 9e75a3e04ee..7adf4dbe0d1 100644 --- a/src/backend/replication/logical/launcher.c +++ b/src/backend/replication/logical/launcher.c @@ -1575,7 +1575,7 @@ CreateConflictDetectionSlot(void) errmsg("creating replication conflict detection slot")); ReplicationSlotCreate(CONFLICT_DETECTION_SLOT, false, RS_PERSISTENT, false, - false, false); + false, false, false); init_conflict_slot_xmin(); } diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c index 8ceaf64d164..d8e02c53558 100644 --- a/src/backend/replication/logical/logical.c +++ b/src/backend/replication/logical/logical.c @@ -108,9 +108,9 @@ static void LoadOutputPlugin(OutputPluginCallbacks *callbacks, const char *plugi * decoding. */ void -CheckLogicalDecodingRequirements(void) +CheckLogicalDecodingRequirements(bool repack) { - CheckSlotRequirements(); + CheckSlotRequirements(repack); /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() @@ -304,6 +304,7 @@ StartupDecodingContext(List *output_plugin_options, * output_plugin_options -- contains options passed to the output plugin * need_full_snapshot -- if true, must obtain a snapshot able to read all * tables; if false, one that can read only catalogs is acceptable. + * for_repack -- if true, we're going to be decoding for REPACK. * restart_lsn -- if given as invalid, it's this routine's responsibility to * mark WAL as reserved by setting a convenient restart_lsn for the slot. * Otherwise, we set for decoding to start from the given LSN without @@ -324,6 +325,7 @@ LogicalDecodingContext * CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, @@ -340,7 +342,7 @@ CreateInitDecodingContext(const char *plugin, * On a standby, this check is also required while creating the slot. * Check the comments in the function. */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(for_repack); /* shorter lines... */ slot = MyReplicationSlot; diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index 9760818941d..512013b0ef0 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -115,7 +115,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); if (PG_ARGISNULL(0)) ereport(ERROR, diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index 8b53bd3ac7f..ae900f13467 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -434,7 +434,7 @@ get_local_synced_slots(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -823,6 +823,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid, */ ReplicationSlotCreate(remote_slot->name, true, RS_TEMPORARY, remote_slot->two_phase, + false, remote_slot->failover, true); @@ -1707,7 +1708,7 @@ update_synced_slots_inactive_since(void) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index a1f37e59dbc..e6722fc0212 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -160,6 +160,8 @@ ReplicationSlot *MyReplicationSlot = NULL; /* GUC variables */ int max_replication_slots = 10; /* the maximum number of replication * slots */ +int max_repack_replication_slots = 5; /* the maximum number of slots + * for REPACK */ /* * Invalidate replication slots that have remained idle longer than this @@ -199,12 +201,13 @@ ReplicationSlotsShmemRequest(void *arg) { Size size; - if (max_replication_slots == 0) + if (max_replication_slots + max_repack_replication_slots == 0) return; size = offsetof(ReplicationSlotCtlData, replication_slots); size = add_size(size, - mul_size(max_replication_slots, sizeof(ReplicationSlot))); + mul_size(max_replication_slots + max_repack_replication_slots, + sizeof(ReplicationSlot))); ShmemRequestStruct(.name = "ReplicationSlot Ctl", .size = size, .ptr = (void **) &ReplicationSlotCtl, @@ -217,7 +220,7 @@ ReplicationSlotsShmemRequest(void *arg) static void ReplicationSlotsShmemInit(void *arg) { - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[i]; @@ -366,6 +369,7 @@ IsSlotForConflictCheck(const char *name) * db_specific: logical decoding is db specific; if the slot is going to * be used for that pass true, otherwise false. * two_phase: If enabled, allows decoding of prepared transactions. + * repack: If true, use a slot from the pool for REPACK. * failover: If enabled, allows the slot to be synced to standbys so * that logical replication can be resumed after failover. * synced: True if the slot is synchronized from the primary server. @@ -373,10 +377,11 @@ IsSlotForConflictCheck(const char *name) void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, bool synced) + bool two_phase, bool repack, bool failover, bool synced) { ReplicationSlot *slot = NULL; - int i; + int startpoint, + endpoint; Assert(MyReplicationSlot == NULL); @@ -425,12 +430,16 @@ ReplicationSlotCreate(const char *name, bool db_specific, LWLockAcquire(ReplicationSlotAllocationLock, LW_EXCLUSIVE); /* - * Check for name collision, and identify an allocatable slot. We need to - * hold ReplicationSlotControlLock in shared mode for this, so that nobody - * else can change the in_use flags while we're looking at them. + * Check for name collision (across the whole array), and identify an + * allocatable slot (in the array slice specific to our current use case: + * either general, or REPACK only). We need to hold + * ReplicationSlotControlLock in shared mode for this, so that nobody else + * can change the in_use flags while we're looking at them. */ LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + startpoint = !repack ? 0 : max_replication_slots; + endpoint = max_replication_slots + (repack ? max_repack_replication_slots : 0); + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -438,7 +447,9 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("replication slot \"%s\" already exists", name))); - if (!s->in_use && slot == NULL) + + if (i >= startpoint && i < endpoint && + !s->in_use && slot == NULL) slot = s; } LWLockRelease(ReplicationSlotControlLock); @@ -448,7 +459,8 @@ ReplicationSlotCreate(const char *name, bool db_specific, ereport(ERROR, (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), errmsg("all replication slots are in use"), - errhint("Free one or increase \"max_replication_slots\"."))); + errhint("Free one or increase \"%s\".", + repack ? "max_repack_replication_slots" : "max_replication_slots"))); /* * Since this slot is not in use, nobody should be looking at any part of @@ -541,7 +553,7 @@ SearchNamedReplicationSlot(const char *name, bool need_lock) if (need_lock) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -569,7 +581,8 @@ int ReplicationSlotIndex(ReplicationSlot *slot) { Assert(slot >= ReplicationSlotCtl->replication_slots && - slot < ReplicationSlotCtl->replication_slots + max_replication_slots); + slot < ReplicationSlotCtl->replication_slots + + (max_replication_slots + max_repack_replication_slots)); return slot - ReplicationSlotCtl->replication_slots; } @@ -863,7 +876,7 @@ ReplicationSlotCleanup(bool synced_only) restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; @@ -1245,7 +1258,7 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked) if (!already_locked) LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; TransactionId effective_xmin; @@ -1300,7 +1313,7 @@ ReplicationSlotsComputeRequiredLSN(void) Assert(ReplicationSlotCtl != NULL); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; XLogRecPtr restart_lsn; @@ -1367,12 +1380,12 @@ ReplicationSlotsComputeLogicalRestartLSN(void) XLogRecPtr result = InvalidXLogRecPtr; int i; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return InvalidXLogRecPtr; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; XLogRecPtr restart_lsn; @@ -1447,11 +1460,11 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive) *nslots = *nactive = 0; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; @@ -1508,13 +1521,13 @@ ReplicationSlotsDropDBSlots(Oid dboid) bool found_valid_logicalslot; bool dropped = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; char *slotname; @@ -1611,11 +1624,11 @@ CheckLogicalSlotExists(void) { bool found = false; - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s; bool invalidated; @@ -1649,17 +1662,24 @@ CheckLogicalSlotExists(void) * slots. */ void -CheckSlotRequirements(void) +CheckSlotRequirements(bool repack) { /* * NB: Adding a new requirement likely means that RestoreSlotFromDisk() * needs the same check. */ - if (max_replication_slots == 0) + if (!repack && max_replication_slots == 0) ereport(ERROR, - (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), - errmsg("replication slots can only be used if \"max_replication_slots\" > 0"))); + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("replication slots can only be used if \"%s\" > 0", + "max_replication_slots")); + + if (repack && max_repack_replication_slots == 0) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("REPACK can only be used if \"%s\" > 0", + "max_repack_replication_slots")); if (wal_level < WAL_LEVEL_REPLICA) ereport(ERROR, @@ -2210,7 +2230,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, Assert(!(possible_causes & RS_INVAL_WAL_REMOVED) || oldestSegno > 0); Assert(possible_causes != RS_INVAL_NONE); - if (max_replication_slots == 0) + if (max_replication_slots == 0 && max_repack_replication_slots == 0) return invalidated; XLogSegNoOffsetToRecPtr(oldestSegno, 0, wal_segment_size, oldestLSN); @@ -2218,7 +2238,7 @@ InvalidateObsoleteReplicationSlots(uint32 possible_causes, restart: found_valid_logicalslot = false; LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; bool released_lock = false; @@ -2323,7 +2343,7 @@ CheckPointReplicationSlots(bool is_shutdown) */ LWLockAcquire(ReplicationSlotAllocationLock, LW_SHARED); - for (i = 0; i < max_replication_slots; i++) + for (i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; char path[MAXPGPATH]; @@ -2424,7 +2444,7 @@ StartupReplicationSlots(void) FreeDir(replication_dir); /* currently no slots exist, we're done. */ - if (max_replication_slots <= 0) + if (max_replication_slots + max_repack_replication_slots <= 0) return; /* Now that we have recovered all the data, compute replication xmin */ diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c index 9f5e4f998fe..16fbd383735 100644 --- a/src/backend/replication/slotfuncs.c +++ b/src/backend/replication/slotfuncs.c @@ -53,7 +53,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve, /* acquire replication slot, this will check for conflicting names */ ReplicationSlotCreate(name, false, temporary ? RS_TEMPORARY : RS_PERSISTENT, false, - false, false); + false, false, false); if (immediately_reserve) { @@ -90,7 +90,7 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); create_physical_replication_slot(NameStr(*name), immediately_reserve, @@ -146,7 +146,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ReplicationSlotCreate(name, true, temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase, - failover, false); + false, failover, false); /* * Ensure the logical decoding is enabled before initializing the logical @@ -164,6 +164,7 @@ create_logical_replication_slot(char *name, char *plugin, */ ctx = CreateInitDecodingContext(plugin, NIL, false, /* just catalogs is OK */ + false, /* not repack */ restart_lsn, XL_ROUTINE(.page_read = read_local_xlog_page, .segment_open = wal_segment_open, @@ -203,7 +204,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); create_logical_replication_slot(NameStr(*name), NameStr(*plugin), @@ -240,7 +241,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS) CheckSlotPermissions(); - CheckSlotRequirements(); + CheckSlotRequirements(false); ReplicationSlotDrop(NameStr(*name), true); @@ -270,7 +271,7 @@ pg_get_replication_slots(PG_FUNCTION_ARGS) currlsn = GetXLogWriteRecPtr(); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); - for (slotno = 0; slotno < max_replication_slots; slotno++) + for (slotno = 0; slotno < max_replication_slots + max_repack_replication_slots; slotno++) { ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno]; ReplicationSlot slot_contents; @@ -648,9 +649,9 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) CheckSlotPermissions(); if (logical_slot) - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); else - CheckSlotRequirements(); + CheckSlotRequirements(false); LWLockAcquire(ReplicationSlotControlLock, LW_SHARED); @@ -665,7 +666,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot) * managed to create the new slot, we advance the new slot's restart_lsn * to the source slot's updated restart_lsn the second time we lock it. */ - for (int i = 0; i < max_replication_slots; i++) + for (int i = 0; i < max_replication_slots + max_repack_replication_slots; i++) { ReplicationSlot *s = &ReplicationSlotCtl->replication_slots[i]; diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index b4a2117a7f9..bad45adb004 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1241,7 +1241,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) { ReplicationSlotCreate(cmd->slotname, false, cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT, - false, false, false); + false, false, false, false); if (reserve_wal) { @@ -1261,7 +1261,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(cmd->kind == REPLICATION_KIND_LOGICAL); - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); /* * Initially create persistent slot as ephemeral - that allows us to @@ -1272,7 +1272,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) */ ReplicationSlotCreate(cmd->slotname, true, cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL, - two_phase, failover, false); + two_phase, false, failover, false); /* * Do options check early so that we can bail before calling the @@ -1330,6 +1330,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd) Assert(IsLogicalDecodingEnabled()); ctx = CreateInitDecodingContext(cmd->plugin, NIL, need_full_snapshot, + false, InvalidXLogRecPtr, XL_ROUTINE(.page_read = logical_read_xlog_page, .segment_open = WalSndSegmentOpen, @@ -1487,7 +1488,7 @@ StartLogicalReplication(StartReplicationCmd *cmd) QueryCompletion qc; /* make sure that our requirements are still fulfilled */ - CheckLogicalDecodingRequirements(); + CheckLogicalDecodingRequirements(false); Assert(!MyReplicationSlot); diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index fcb6ab80583..632f3ba4989 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -2079,6 +2079,14 @@ max => 'MAX_BACKENDS', }, +{ name => 'max_repack_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', + short_desc => 'Sets the maximum number of replication slots for use by REPACK.', + variable => 'max_repack_replication_slots', + boot_val => '5', + min => '0', + max => 'MAX_BACKENDS', +}, + /* see max_wal_senders */ { name => 'max_replication_slots', type => 'int', context => 'PGC_POSTMASTER', group => 'REPLICATION_SENDING', short_desc => 'Sets the maximum number of simultaneously defined replication slots.', diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e3e462f3efb..2e10eb4a36a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -348,6 +348,8 @@ # (change requires restart) #max_replication_slots = 10 # max number of replication slots # (change requires restart) +#max_repack_replication_slots = 5 # max number of replication slots for REPACK + # (change requires restart) #wal_keep_size = 0 # in megabytes; 0 disables #max_slot_wal_keep_size = -1 # in megabytes; -1 disables #idle_replication_slot_timeout = 0 # in seconds; 0 disables diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h index bc9d4ece672..bc075b16741 100644 --- a/src/include/replication/logical.h +++ b/src/include/replication/logical.h @@ -115,11 +115,12 @@ typedef struct LogicalDecodingContext } LogicalDecodingContext; -extern void CheckLogicalDecodingRequirements(void); +extern void CheckLogicalDecodingRequirements(bool repack); extern LogicalDecodingContext *CreateInitDecodingContext(const char *plugin, List *output_plugin_options, bool need_full_snapshot, + bool for_repack, XLogRecPtr restart_lsn, XLogReaderRoutine *xl_routine, LogicalOutputPluginWriterPrepareWrite prepare_write, diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index 1a3557de607..77c8d0975b6 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -324,13 +324,14 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; +extern PGDLLIMPORT int max_repack_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* management of individual slots */ extern void ReplicationSlotCreate(const char *name, bool db_specific, ReplicationSlotPersistency persistency, - bool two_phase, bool failover, + bool two_phase, bool repack, bool failover, bool synced); extern void ReplicationSlotPersist(void); extern void ReplicationSlotDrop(const char *name, bool nowait); @@ -373,7 +374,7 @@ extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname extern void StartupReplicationSlots(void); extern void CheckPointReplicationSlots(bool is_shutdown); -extern void CheckSlotRequirements(void); +extern void CheckSlotRequirements(bool repack); extern void CheckSlotPermissions(void); extern ReplicationSlotInvalidationCause GetSlotInvalidationCause(const char *cause_name); -- 2.47.3 --qs77q6fpwolne4ds Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v56-0003-Error-out-any-process-that-would-block-at-REPACK.patch" ^ permalink raw reply [nested|flat] 199+ messages in thread
end of thread, other threads:[~2026-04-01 17:54 UTC | newest] Thread overview: 199+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2025-08-11 13:22 [PATCH 1/4] Add REPACK command. Antonin Houska <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v53 7/7] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v50 8/8] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v52 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v54 5/5] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v51 09/10] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]> 2026-04-01 17:54 [PATCH v56 2/3] Reserve replication slots specifically for REPACK Álvaro Herrera <[email protected]>
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