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* [PATCH 3/3] Extended statistics on expressions
@ 2020-12-03 15:19 Tomas Vondra <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Tomas Vondra @ 2020-12-03 15:19 UTC (permalink / raw)
Allow defining extended statistics on expressions, not just simple
column references. With this commit, it's possible to do things like
CREATE TABLE t (a int);
CREATE STATISTICS s ON mod(a,10), mod(a,20) FROM t;
and the collected statistics will be useful for estimating queries
using those expressions in various places, like
SELECT * FROM t WHERE mod(a,10) = 0 AND mod(a,20) = 0;
or
SELECT mod(a,10), mod(a,20) FROM t GROUP BY 1, 2;
The commit also adds a new statistics type "expressions" which builds
the usual per-column statistics for each expression, allowing better
estimates even for queries with just a single expression, which are
not affected by multi-column statistics. This achieves the same goal
as creating expression indexes, without index maintenance overhead.
---
doc/src/sgml/catalogs.sgml | 238 ++-
doc/src/sgml/ref/create_statistics.sgml | 98 +-
src/backend/catalog/Makefile | 8 +-
src/backend/catalog/system_views.sql | 71 +
src/backend/commands/statscmds.c | 319 +++-
src/backend/nodes/copyfuncs.c | 14 +
src/backend/nodes/equalfuncs.c | 13 +
src/backend/nodes/outfuncs.c | 12 +
src/backend/optimizer/util/plancat.c | 62 +
src/backend/parser/gram.y | 38 +-
src/backend/parser/parse_agg.c | 10 +
src/backend/parser/parse_expr.c | 6 +
src/backend/parser/parse_func.c | 3 +
src/backend/parser/parse_utilcmd.c | 121 +-
src/backend/statistics/dependencies.c | 369 +++-
src/backend/statistics/extended_stats.c | 1558 ++++++++++++++++-
src/backend/statistics/mcv.c | 295 +++-
src/backend/statistics/mvdistinct.c | 101 +-
src/backend/tcop/utility.c | 23 +-
src/backend/utils/adt/ruleutils.c | 269 ++-
src/backend/utils/adt/selfuncs.c | 447 ++++-
src/bin/pg_dump/t/002_pg_dump.pl | 12 +
src/bin/psql/describe.c | 66 +-
src/include/catalog/pg_proc.dat | 8 +
src/include/catalog/pg_statistic_ext.h | 4 +
src/include/catalog/pg_statistic_ext_data.h | 1 +
src/include/nodes/nodes.h | 1 +
src/include/nodes/parsenodes.h | 16 +
src/include/nodes/pathnodes.h | 3 +-
src/include/parser/parse_node.h | 1 +
src/include/parser/parse_utilcmd.h | 2 +
.../statistics/extended_stats_internal.h | 40 +-
src/include/statistics/statistics.h | 2 +
.../regress/expected/create_table_like.out | 20 +-
src/test/regress/expected/rules.out | 75 +
src/test/regress/expected/stats_ext.out | 681 ++++++-
src/test/regress/sql/create_table_like.sql | 2 +
src/test/regress/sql/stats_ext.sql | 313 +++-
38 files changed, 4944 insertions(+), 378 deletions(-)
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 43d7a1ad90..eef546a23f 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -7347,7 +7347,7 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l
<structfield>stxkind</structfield> <type>char[]</type>
</para>
<para>
- An array containing codes for the enabled statistic kinds;
+ An array containing codes for the enabled statistics kinds;
valid values are:
<literal>d</literal> for n-distinct statistics,
<literal>f</literal> for functional dependency statistics, and
@@ -9396,6 +9396,11 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l
<entry>extended planner statistics</entry>
</row>
+ <row>
+ <entry><link linkend="view-pg-stats-ext-exprs"><structname>pg_stats_ext_exprs</structname></link></entry>
+ <entry>extended planner statistics for expressions</entry>
+ </row>
+
<row>
<entry><link linkend="view-pg-tables"><structname>pg_tables</structname></link></entry>
<entry>tables</entry>
@@ -12958,6 +12963,237 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
</sect1>
+ <sect1 id="view-pg-stats-ext-exprs">
+ <title><structname>pg_stats_ext_exprs</structname></title>
+
+ <indexterm zone="view-pg-stats-ext-exprs">
+ <primary>pg_stats_ext_exprs</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_stats_ext_exprs</structname> provides access to
+ the information stored in the <link
+ linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
+ and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ catalogs. This view allows access only to rows of
+ <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link> and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ that correspond to tables the user has permission to read, and therefore
+ it is safe to allow public read access to this view.
+ </para>
+
+ <para>
+ <structname>pg_stats_ext_exprs</structname> is also designed to present
+ the information in a more readable format than the underlying catalogs
+ — at the cost that its schema must be extended whenever the structure
+ of statistics in <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link> changes.
+ </para>
+
+ <table>
+ <title><structname>pg_stats_ext_exprs</structname> Columns</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>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing extended statistic
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_name</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.<structfield>stxname</structfield>)
+ </para>
+ <para>
+ Name of extended statistics
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_owner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Owner of the extended statistics
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>expr</structfield> <type>text</type>
+ </para>
+ <para>
+ Expression the extended statistics is defined on
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>null_frac</structfield> <type>float4</type>
+ </para>
+ <para>
+ Fraction of column entries that are null
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>avg_width</structfield> <type>int4</type>
+ </para>
+ <para>
+ Average width in bytes of column's entries
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>n_distinct</structfield> <type>float4</type>
+ </para>
+ <para>
+ If greater than zero, the estimated number of distinct values in the
+ column. If less than zero, the negative of the number of distinct
+ values divided by the number of rows. (The negated form is used when
+ <command>ANALYZE</command> believes that the number of distinct values is
+ likely to increase as the table grows; the positive form is used when
+ the column seems to have a fixed number of possible values.) For
+ example, -1 indicates a unique column in which the number of distinct
+ values is the same as the number of rows.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_vals</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of the most common values in the column. (Null if
+ no values seem to be more common than any others.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common values,
+ i.e., number of occurrences of each divided by total number of rows.
+ (Null when <structfield>most_common_vals</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>histogram_bounds</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of values that divide the column's values into groups of
+ approximately equal population. The values in
+ <structfield>most_common_vals</structfield>, if present, are omitted from this
+ histogram calculation. (This column is null if the column data type
+ does not have a <literal><</literal> operator or if the
+ <structfield>most_common_vals</structfield> list accounts for the entire
+ population.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>correlation</structfield> <type>float4</type>
+ </para>
+ <para>
+ Statistical correlation between physical row ordering and
+ logical ordering of the column values. This ranges from -1 to +1.
+ When the value is near -1 or +1, an index scan on the column will
+ be estimated to be cheaper than when it is near zero, due to reduction
+ of random access to the disk. (This column is null if the column data
+ type does not have a <literal><</literal> operator.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elems</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of non-null element values most often appearing within values of
+ the column. (Null for scalar types.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elem_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common element values, i.e., the
+ fraction of rows containing at least one instance of the given value.
+ Two or three additional values follow the per-element frequencies;
+ these are the minimum and maximum of the preceding per-element
+ frequencies, and optionally the frequency of null elements.
+ (Null when <structfield>most_common_elems</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>elem_count_histogram</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A histogram of the counts of distinct non-null element values within the
+ values of the column, followed by the average number of distinct
+ non-null elements. (Null for scalar types.)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The maximum number of entries in the array fields can be controlled on a
+ column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
+ TABLE SET STATISTICS</command></link>
+ command, or globally by setting the
+ <xref linkend="guc-default-statistics-target"/> run-time parameter.
+ </para>
+
+ </sect1>
+
<sect1 id="view-pg-tables">
<title><structname>pg_tables</structname></title>
diff --git a/doc/src/sgml/ref/create_statistics.sgml b/doc/src/sgml/ref/create_statistics.sgml
index 4363be50c3..ba50ee6bcd 100644
--- a/doc/src/sgml/ref/create_statistics.sgml
+++ b/doc/src/sgml/ref/create_statistics.sgml
@@ -21,9 +21,13 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
+CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable>
+ ON ( <replaceable class="parameter">expression</replaceable> )
+ FROM <replaceable class="parameter">table_name</replaceable>
+
CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable>
[ ( <replaceable class="parameter">statistics_kind</replaceable> [, ... ] ) ]
- ON <replaceable class="parameter">column_name</replaceable>, <replaceable class="parameter">column_name</replaceable> [, ...]
+ ON { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [, ...]
FROM <replaceable class="parameter">table_name</replaceable>
</synopsis>
@@ -39,6 +43,16 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
database and will be owned by the user issuing the command.
</para>
+ <para>
+ The <command>CREATE STATISTICS</command> command has two basic forms. The
+ simple variant allows building statistics for a single expression, does
+ not allow specifying any statistics kinds and provides benefits similar
+ to an expression index. The full variant allows defining statistics objects
+ on multiple columns and expressions, and selecting which statistics kinds will
+ be built. The per-expression statistics are built automatically when there
+ is at least one expression.
+ </para>
+
<para>
If a schema name is given (for example, <literal>CREATE STATISTICS
myschema.mystat ...</literal>) then the statistics object is created in the
@@ -86,7 +100,9 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
dependency statistics, and <literal>mcv</literal> which enables
most-common values lists.
If this clause is omitted, all supported statistics kinds are
- included in the statistics object.
+ included in the statistics object. Expression statistics are built
+ automatically when the statistics definition includes complex
+ expressions and not just simple column references.
For more information, see <xref linkend="planner-stats-extended"/>
and <xref linkend="multivariate-statistics-examples"/>.
</para>
@@ -104,6 +120,17 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><replaceable class="parameter">expression</replaceable></term>
+ <listitem>
+ <para>
+ The expression to be covered by the computed statistics. In this case
+ only a single expression is required, in which case only statistics
+ for the expression are built.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><replaceable class="parameter">table_name</replaceable></term>
<listitem>
@@ -125,6 +152,13 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
reading it. Once created, however, the ownership of the statistics
object is independent of the underlying table(s).
</para>
+
+ <para>
+ Expression statistics are per-expression and are similar to creating an
+ index on the expression, except that they avoid the overhead of index
+ maintenance. Expression statistics are built automatically when there
+ is at least one expression in the statistics object definition.
+ </para>
</refsect1>
<refsect1 id="sql-createstatistics-examples">
@@ -196,6 +230,66 @@ EXPLAIN ANALYZE SELECT * FROM t2 WHERE (a = 1) AND (b = 2);
in the table, allowing it to generate better estimates in both cases.
</para>
+ <para>
+ Create table <structname>t3</structname> with a single timestamp column,
+ and run a query using an expression on that column. Without extended
+ statistics, the planner has no information about data distribution for
+ results of those expression, and uses default estimates as illustrated
+ by the first query. The planner also does not realize that the value of
+ the second column fully defines the value of the other column, because
+ date truncated to day still identifies the month. Then expression and
+ ndistinct statistics are built on those two columns:
+
+<programlisting>
+CREATE TABLE t3 (
+ a timestamp
+);
+
+INSERT INTO t3 SELECT i FROM generate_series('2020-01-01'::timestamp,
+ '2020-12-31'::timestamp,
+ '1 minute'::interval) s(i);
+
+ANALYZE t3;
+
+-- the number of matching rows will be drastically underestimated:
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('month', a) = '2020-01-01'::timestamp;
+
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('day', a) BETWEEN '2020-01-01'::timestamp
+ AND '2020-06-30'::timestamp;
+
+EXPLAIN ANALYZE SELECT date_trunc('month', a), date_trunc('day', a)
+ FROM t3 GROUP BY 1, 2;
+
+-- per-expression statistics are built automatically
+CREATE STATISTICS s3 (ndistinct) ON date_trunc('month', a), date_trunc('day', a) FROM t3;
+
+ANALYZE t1;
+
+-- now the row count estimates are more accurate:
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('month', a) = '2020-01-01'::timestamp;
+
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('day', a) BETWEEN '2020-01-01'::timestamp
+ AND '2020-06-30'::timestamp;
+
+EXPLAIN ANALYZE SELECT date_trunc('month', a), date_trunc('day', a)
+ FROM t3 GROUP BY 1, 2;
+</programlisting>
+
+ Without expression and ndistinct statistics, the planner would assume
+ that the two <literal>WHERE</literal> and <literal>GROUP BY</literal>
+ conditions are independent, and would multiply their selectivities
+ together to arrive at a much-too-small row count estimate in the first
+ two queries, and a much-too-high group count estimate in the aggregate
+ query. This is further exacerbated by the lack of accurate statistics
+ for the expressions, forcing the planner to use default selectivities.
+ With such statistics, the planner recognizes that the conditions are
+ correlated and arrives at much more accurate estimates.
+ </para>
+
</refsect1>
<refsect1>
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index c85f0ca7b6..fa91ff1c42 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -49,15 +49,15 @@ include $(top_srcdir)/src/backend/common.mk
# Note: the order of this list determines the order in which the catalog
# header files are assembled into postgres.bki. BKI_BOOTSTRAP catalogs
-# must appear first, and there are reputedly other, undocumented ordering
-# dependencies.
+# must appear first, and pg_statistic before pg_statistic_ext_data, and
+# there are reputedly other, undocumented ordering dependencies.
CATALOG_HEADERS := \
pg_proc.h pg_type.h pg_attribute.h pg_class.h \
pg_attrdef.h pg_constraint.h pg_inherits.h pg_index.h pg_operator.h \
pg_opfamily.h pg_opclass.h pg_am.h pg_amop.h pg_amproc.h \
pg_language.h pg_largeobject_metadata.h pg_largeobject.h pg_aggregate.h \
- pg_statistic_ext.h pg_statistic_ext_data.h \
- pg_statistic.h pg_rewrite.h pg_trigger.h pg_event_trigger.h pg_description.h \
+ pg_statistic.h pg_statistic_ext.h pg_statistic_ext_data.h \
+ pg_rewrite.h pg_trigger.h pg_event_trigger.h pg_description.h \
pg_cast.h pg_enum.h pg_namespace.h pg_conversion.h pg_depend.h \
pg_database.h pg_db_role_setting.h pg_tablespace.h \
pg_authid.h pg_auth_members.h pg_shdepend.h pg_shdescription.h \
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index fa58afd9d7..32ad93db3f 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -264,6 +264,7 @@ CREATE VIEW pg_stats_ext WITH (security_barrier) AS
JOIN pg_attribute a
ON (a.attrelid = s.stxrelid AND a.attnum = k)
) AS attnames,
+ pg_get_statisticsobjdef_expressions(s.oid) as exprs,
s.stxkind AS kinds,
sd.stxdndistinct AS n_distinct,
sd.stxddependencies AS dependencies,
@@ -290,6 +291,76 @@ CREATE VIEW pg_stats_ext WITH (security_barrier) AS
WHERE NOT has_column_privilege(c.oid, a.attnum, 'select') )
AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+CREATE VIEW pg_stats_ext_exprs WITH (security_barrier) AS
+ SELECT cn.nspname AS schemaname,
+ c.relname AS tablename,
+ sn.nspname AS statistics_schemaname,
+ s.stxname AS statistics_name,
+ pg_get_userbyid(s.stxowner) AS statistics_owner,
+ stat_exprs.expr,
+ (stat.a).stanullfrac AS null_frac,
+ (stat.a).stawidth AS avg_width,
+ (stat.a).stadistinct AS n_distinct,
+ (CASE
+ WHEN (stat.a).stakind1 = 1 THEN (stat.a).stavalues1
+ WHEN (stat.a).stakind2 = 1 THEN (stat.a).stavalues2
+ WHEN (stat.a).stakind3 = 1 THEN (stat.a).stavalues3
+ WHEN (stat.a).stakind4 = 1 THEN (stat.a).stavalues4
+ WHEN (stat.a).stakind5 = 1 THEN (stat.a).stavalues5
+ END) AS most_common_vals,
+ (CASE
+ WHEN (stat.a).stakind1 = 1 THEN (stat.a).stanumbers1
+ WHEN (stat.a).stakind2 = 1 THEN (stat.a).stanumbers2
+ WHEN (stat.a).stakind3 = 1 THEN (stat.a).stanumbers3
+ WHEN (stat.a).stakind4 = 1 THEN (stat.a).stanumbers4
+ WHEN (stat.a).stakind5 = 1 THEN (stat.a).stanumbers5
+ END) AS most_common_freqs,
+ (CASE
+ WHEN (stat.a).stakind1 = 2 THEN (stat.a).stavalues1
+ WHEN (stat.a).stakind2 = 2 THEN (stat.a).stavalues2
+ WHEN (stat.a).stakind3 = 2 THEN (stat.a).stavalues3
+ WHEN (stat.a).stakind4 = 2 THEN (stat.a).stavalues4
+ WHEN (stat.a).stakind5 = 2 THEN (stat.a).stavalues5
+ END) AS histogram_bounds,
+ (CASE
+ WHEN (stat.a).stakind1 = 3 THEN (stat.a).stanumbers1[1]
+ WHEN (stat.a).stakind2 = 3 THEN (stat.a).stanumbers2[1]
+ WHEN (stat.a).stakind3 = 3 THEN (stat.a).stanumbers3[1]
+ WHEN (stat.a).stakind4 = 3 THEN (stat.a).stanumbers4[1]
+ WHEN (stat.a).stakind5 = 3 THEN (stat.a).stanumbers5[1]
+ END) correlation,
+ (CASE
+ WHEN (stat.a).stakind1 = 4 THEN (stat.a).stavalues1
+ WHEN (stat.a).stakind2 = 4 THEN (stat.a).stavalues2
+ WHEN (stat.a).stakind3 = 4 THEN (stat.a).stavalues3
+ WHEN (stat.a).stakind4 = 4 THEN (stat.a).stavalues4
+ WHEN (stat.a).stakind5 = 4 THEN (stat.a).stavalues5
+ END) AS most_common_elems,
+ (CASE
+ WHEN (stat.a).stakind1 = 4 THEN (stat.a).stanumbers1
+ WHEN (stat.a).stakind2 = 4 THEN (stat.a).stanumbers2
+ WHEN (stat.a).stakind3 = 4 THEN (stat.a).stanumbers3
+ WHEN (stat.a).stakind4 = 4 THEN (stat.a).stanumbers4
+ WHEN (stat.a).stakind5 = 4 THEN (stat.a).stanumbers5
+ END) AS most_common_elem_freqs,
+ (CASE
+ WHEN (stat.a).stakind1 = 5 THEN (stat.a).stanumbers1
+ WHEN (stat.a).stakind2 = 5 THEN (stat.a).stanumbers2
+ WHEN (stat.a).stakind3 = 5 THEN (stat.a).stanumbers3
+ WHEN (stat.a).stakind4 = 5 THEN (stat.a).stanumbers4
+ WHEN (stat.a).stakind5 = 5 THEN (stat.a).stanumbers5
+ END) AS elem_count_histogram
+ FROM pg_statistic_ext s JOIN pg_class c ON (c.oid = s.stxrelid)
+ LEFT JOIN pg_statistic_ext_data sd ON (s.oid = sd.stxoid)
+ LEFT JOIN pg_namespace cn ON (cn.oid = c.relnamespace)
+ LEFT JOIN pg_namespace sn ON (sn.oid = s.stxnamespace)
+ JOIN LATERAL (
+ SELECT unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr
+ ) stat_exprs ON (stat_exprs.expr IS NOT NULL)
+ LEFT JOIN LATERAL (
+ SELECT unnest(sd.stxdexpr)::pg_statistic AS a
+ ) stat ON (TRUE);
+
-- unprivileged users may read pg_statistic_ext but not pg_statistic_ext_data
REVOKE ALL on pg_statistic_ext_data FROM public;
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 2bae205845..7370af820f 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -29,6 +29,8 @@
#include "commands/comment.h"
#include "commands/defrem.h"
#include "miscadmin.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/optimizer.h"
#include "statistics/statistics.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
@@ -62,7 +64,8 @@ ObjectAddress
CreateStatistics(CreateStatsStmt *stmt)
{
int16 attnums[STATS_MAX_DIMENSIONS];
- int numcols = 0;
+ int nattnums = 0;
+ int numcols;
char *namestr;
NameData stxname;
Oid statoid;
@@ -74,21 +77,25 @@ CreateStatistics(CreateStatsStmt *stmt)
Datum datavalues[Natts_pg_statistic_ext_data];
bool datanulls[Natts_pg_statistic_ext_data];
int2vector *stxkeys;
+ List *stxexprs = NIL;
+ Datum exprsDatum;
Relation statrel;
Relation datarel;
Relation rel = NULL;
Oid relid;
ObjectAddress parentobject,
myself;
- Datum types[3]; /* one for each possible type of statistic */
+ Datum types[4]; /* one for each possible type of statistic */
int ntypes;
ArrayType *stxkind;
bool build_ndistinct;
bool build_dependencies;
bool build_mcv;
+ bool build_expressions;
bool requested_type = false;
int i;
ListCell *cell;
+ ListCell *cell2;
Assert(IsA(stmt, CreateStatsStmt));
@@ -190,72 +197,169 @@ CreateStatistics(CreateStatsStmt *stmt)
}
/*
- * Currently, we only allow simple column references in the expression
- * list. That will change someday, and again the grammar already supports
- * it so we have to enforce restrictions here. For now, we can convert
- * the expression list to a simple array of attnums. While at it, enforce
- * some constraints.
+ * Make sure no more than STATS_MAX_DIMENSIONS columns are used. There
+ * might be duplicates and so on, but we'll deal with those later.
+ */
+ numcols = list_length(stmt->exprs);
+ if (numcols > STATS_MAX_DIMENSIONS)
+ ereport(ERROR,
+ (errcode(ERRCODE_TOO_MANY_COLUMNS),
+ errmsg("cannot have more than %d columns in statistics",
+ STATS_MAX_DIMENSIONS)));
+
+ /*
+ * Convert the expression list to a simple array of attnums, but also
+ * keep a list of more complex expressions. While at it, enforce some
+ * constraints.
*/
foreach(cell, stmt->exprs)
{
Node *expr = (Node *) lfirst(cell);
- ColumnRef *cref;
- char *attname;
+ StatsElem *selem;
HeapTuple atttuple;
Form_pg_attribute attForm;
TypeCacheEntry *type;
- if (!IsA(expr, ColumnRef))
+ /*
+ * XXX How could we get anything else than a StatsElem, given the
+ * grammar? But let's keep it as a safety, maybe shall we turn it
+ * into an assert?
+ */
+ if (!IsA(expr, StatsElem))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("only simple column references are allowed in CREATE STATISTICS")));
- cref = (ColumnRef *) expr;
+ errmsg("only simple column references and expressions are allowed in CREATE STATISTICS")));
- if (list_length(cref->fields) != 1)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("only simple column references are allowed in CREATE STATISTICS")));
- attname = strVal((Value *) linitial(cref->fields));
+ selem = (StatsElem *) expr;
- atttuple = SearchSysCacheAttName(relid, attname);
- if (!HeapTupleIsValid(atttuple))
- ereport(ERROR,
- (errcode(ERRCODE_UNDEFINED_COLUMN),
- errmsg("column \"%s\" does not exist",
- attname)));
- attForm = (Form_pg_attribute) GETSTRUCT(atttuple);
+ if (selem->name) /* column reference */
+ {
+ char *attname;
+ attname = selem->name;
+
+ atttuple = SearchSysCacheAttName(relid, attname);
+ if (!HeapTupleIsValid(atttuple))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column \"%s\" does not exist",
+ attname)));
+ attForm = (Form_pg_attribute) GETSTRUCT(atttuple);
+
+ /* Disallow use of system attributes in extended stats */
+ if (attForm->attnum <= 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("statistics creation on system columns is not supported")));
+
+ /* Disallow data types without a less-than operator */
+ type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
+ if (type->lt_opr == InvalidOid)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("column \"%s\" cannot be used in statistics because its type %s has no default btree operator class",
+ attname, format_type_be(attForm->atttypid))));
+
+ attnums[nattnums] = attForm->attnum;
+ nattnums++;
+ ReleaseSysCache(atttuple);
+ }
+ else /* expression */
+ {
+ Node *expr = selem->expr;
+ Oid atttype;
+
+ Assert(expr != NULL);
+
+ /*
+ * Disallow data types without a less-than operator.
+ *
+ * We ignore this for statistics on a single expression, in
+ * which case we'll build the regular statistics only (and
+ * that code can deal with such data types).
+ */
+ if (list_length(stmt->exprs) > 1)
+ {
+ atttype = exprType(expr);
+ type = lookup_type_cache(atttype, TYPECACHE_LT_OPR);
+ if (type->lt_opr == InvalidOid)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("expression cannot be used in statistics because its type %s has no default btree operator class",
+ format_type_be(atttype))));
+ }
+
+ stxexprs = lappend(stxexprs, expr);
+ }
+ }
- /* Disallow use of system attributes in extended stats */
- if (attForm->attnum <= 0)
+ /*
+ * Parse the statistics kinds. Firstly, check that this is not the
+ * variant building statistics for a single expression, in which case
+ * we don't allow specifying any statistics kinds. The simple variant
+ * only has one expression, and does not allow statistics kinds.
+ */
+ if ((list_length(stmt->exprs) == 1) && (list_length(stxexprs) == 1))
+ {
+ /* statistics kinds not specified */
+ if (list_length(stmt->stat_types) > 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("statistics creation on system columns is not supported")));
+ errmsg("when building statistics on a single expression, statistics kinds may not be specified")));
+ }
- /* Disallow data types without a less-than operator */
- type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
- if (type->lt_opr == InvalidOid)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("column \"%s\" cannot be used in statistics because its type %s has no default btree operator class",
- attname, format_type_be(attForm->atttypid))));
+ /* OK, let's check that we recognize the statistics kinds. */
+ build_ndistinct = false;
+ build_dependencies = false;
+ build_mcv = false;
+ foreach(cell, stmt->stat_types)
+ {
+ char *type = strVal((Value *) lfirst(cell));
- /* Make sure no more than STATS_MAX_DIMENSIONS columns are used */
- if (numcols >= STATS_MAX_DIMENSIONS)
+ if (strcmp(type, "ndistinct") == 0)
+ {
+ build_ndistinct = true;
+ requested_type = true;
+ }
+ else if (strcmp(type, "dependencies") == 0)
+ {
+ build_dependencies = true;
+ requested_type = true;
+ }
+ else if (strcmp(type, "mcv") == 0)
+ {
+ build_mcv = true;
+ requested_type = true;
+ }
+ else
ereport(ERROR,
- (errcode(ERRCODE_TOO_MANY_COLUMNS),
- errmsg("cannot have more than %d columns in statistics",
- STATS_MAX_DIMENSIONS)));
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("unrecognized statistics kind \"%s\"",
+ type)));
+ }
- attnums[numcols] = attForm->attnum;
- numcols++;
- ReleaseSysCache(atttuple);
+ /*
+ * If no statistic type was specified, build them all (but request
+ * expression stats only when there actually are any expressions).
+ */
+ if (!requested_type)
+ {
+ build_ndistinct = (numcols >= 2);
+ build_dependencies = (numcols >= 2);
+ build_mcv = (numcols >= 2);
}
/*
- * Check that at least two columns were specified in the statement. The
- * upper bound was already checked in the loop above.
+ * When there are non-trivial expressions, build the expression stats
+ * automatically. This allows calculating good estimates for stats that
+ * consider per-clause estimates (e.g. functional dependencies).
+ */
+ build_expressions = (list_length(stxexprs) > 0);
+
+ /*
+ * Check that at least two columns were specified in the statement, or
+ * that we're building statistics on a single expression.
*/
- if (numcols < 2)
+ if ((numcols < 2) && (list_length(stxexprs) != 1))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("extended statistics require at least 2 columns")));
@@ -265,13 +369,13 @@ CreateStatistics(CreateStatsStmt *stmt)
* it does not hurt (it does not affect the efficiency, unlike for
* indexes, for example).
*/
- qsort(attnums, numcols, sizeof(int16), compare_int16);
+ qsort(attnums, nattnums, sizeof(int16), compare_int16);
/*
* Check for duplicates in the list of columns. The attnums are sorted so
* just check consecutive elements.
*/
- for (i = 1; i < numcols; i++)
+ for (i = 1; i < nattnums; i++)
{
if (attnums[i] == attnums[i - 1])
ereport(ERROR,
@@ -279,48 +383,36 @@ CreateStatistics(CreateStatsStmt *stmt)
errmsg("duplicate column name in statistics definition")));
}
- /* Form an int2vector representation of the sorted column list */
- stxkeys = buildint2vector(attnums, numcols);
-
/*
- * Parse the statistics kinds.
+ * Check for duplicate expressions. We do two loops, counting the
+ * occurrences of each expression. This is O(N^2) but we only allow
+ * small number of expressions and it's not executed often.
*/
- build_ndistinct = false;
- build_dependencies = false;
- build_mcv = false;
- foreach(cell, stmt->stat_types)
+ foreach (cell, stxexprs)
{
- char *type = strVal((Value *) lfirst(cell));
+ Node *expr1 = (Node *) lfirst(cell);
+ int cnt = 0;
- if (strcmp(type, "ndistinct") == 0)
- {
- build_ndistinct = true;
- requested_type = true;
- }
- else if (strcmp(type, "dependencies") == 0)
+ foreach (cell2, stxexprs)
{
- build_dependencies = true;
- requested_type = true;
- }
- else if (strcmp(type, "mcv") == 0)
- {
- build_mcv = true;
- requested_type = true;
+ Node *expr2 = (Node *) lfirst(cell2);
+
+ if (equal(expr1, expr2))
+ cnt += 1;
}
- else
+
+ /* every expression should find at least itself */
+ Assert(cnt >= 1);
+
+ if (cnt > 1)
ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("unrecognized statistics kind \"%s\"",
- type)));
- }
- /* If no statistic type was specified, build them all. */
- if (!requested_type)
- {
- build_ndistinct = true;
- build_dependencies = true;
- build_mcv = true;
+ (errcode(ERRCODE_DUPLICATE_COLUMN),
+ errmsg("duplicate expression in statistics definition")));
}
+ /* Form an int2vector representation of the sorted column list */
+ stxkeys = buildint2vector(attnums, nattnums);
+
/* construct the char array of enabled statistic types */
ntypes = 0;
if (build_ndistinct)
@@ -329,9 +421,23 @@ CreateStatistics(CreateStatsStmt *stmt)
types[ntypes++] = CharGetDatum(STATS_EXT_DEPENDENCIES);
if (build_mcv)
types[ntypes++] = CharGetDatum(STATS_EXT_MCV);
+ if (build_expressions)
+ types[ntypes++] = CharGetDatum(STATS_EXT_EXPRESSIONS);
Assert(ntypes > 0 && ntypes <= lengthof(types));
stxkind = construct_array(types, ntypes, CHAROID, 1, true, TYPALIGN_CHAR);
+ /* convert the expressions (if any) to a text datum */
+ if (stxexprs != NIL)
+ {
+ char *exprsString;
+
+ exprsString = nodeToString(stxexprs);
+ exprsDatum = CStringGetTextDatum(exprsString);
+ pfree(exprsString);
+ }
+ else
+ exprsDatum = (Datum) 0;
+
statrel = table_open(StatisticExtRelationId, RowExclusiveLock);
/*
@@ -351,6 +457,10 @@ CreateStatistics(CreateStatsStmt *stmt)
values[Anum_pg_statistic_ext_stxkeys - 1] = PointerGetDatum(stxkeys);
values[Anum_pg_statistic_ext_stxkind - 1] = PointerGetDatum(stxkind);
+ values[Anum_pg_statistic_ext_stxexprs - 1] = exprsDatum;
+ if (exprsDatum == (Datum) 0)
+ nulls[Anum_pg_statistic_ext_stxexprs - 1] = true;
+
/* insert it into pg_statistic_ext */
htup = heap_form_tuple(statrel->rd_att, values, nulls);
CatalogTupleInsert(statrel, htup);
@@ -373,6 +483,7 @@ CreateStatistics(CreateStatsStmt *stmt)
datanulls[Anum_pg_statistic_ext_data_stxdndistinct - 1] = true;
datanulls[Anum_pg_statistic_ext_data_stxddependencies - 1] = true;
datanulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
+ datanulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = true;
/* insert it into pg_statistic_ext_data */
htup = heap_form_tuple(datarel->rd_att, datavalues, datanulls);
@@ -396,12 +507,39 @@ CreateStatistics(CreateStatsStmt *stmt)
*/
ObjectAddressSet(myself, StatisticExtRelationId, statoid);
- for (i = 0; i < numcols; i++)
+ /* add dependencies for plain column references */
+ for (i = 0; i < nattnums; i++)
{
ObjectAddressSubSet(parentobject, RelationRelationId, relid, attnums[i]);
recordDependencyOn(&myself, &parentobject, DEPENDENCY_AUTO);
}
+ /*
+ * If there are no simply-referenced columns, give the statistics an
+ * auto dependency on the whole table. In most cases, this will
+ * be redundant, but it might not be if the statistics expressions
+ * contain no Vars (which might seem strange but possible).
+ *
+ * XXX This is copied from index_create, not sure if it's applicable
+ * to extended statistics too.
+ */
+ if (!nattnums)
+ {
+ ObjectAddressSet(parentobject, RelationRelationId, relid);
+ recordDependencyOn(&myself, &parentobject, DEPENDENCY_AUTO);
+ }
+
+ /*
+ * Store dependencies on anything mentioned in statistics expressions,
+ * just like we do for index expressions.
+ */
+ if (stxexprs)
+ recordDependencyOnSingleRelExpr(&myself,
+ (Node *) stxexprs,
+ relid,
+ DEPENDENCY_NORMAL,
+ DEPENDENCY_AUTO, false, true);
+
/*
* Also add dependencies on namespace and owner. These are required
* because the stats object might have a different namespace and/or owner
@@ -625,7 +763,7 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
elog(ERROR, "cache lookup failed for statistics object %u", statsOid);
/*
- * When none of the defined statistics types contain datum values from the
+ * When none of the defined statistics kinds contain datum values from the
* table's columns then there's no need to reset the stats. Functional
* dependencies and ndistinct stats should still hold true.
*/
@@ -637,7 +775,7 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
/*
* OK, we need to reset some statistics. So let's build the new tuple,
- * replacing the affected statistics types with NULL.
+ * replacing the affected statistics kinds with NULL.
*/
memset(nulls, 0, Natts_pg_statistic_ext_data * sizeof(bool));
memset(replaces, 0, Natts_pg_statistic_ext_data * sizeof(bool));
@@ -645,6 +783,7 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
replaces[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
+ nulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = true;
rel = table_open(StatisticExtDataRelationId, RowExclusiveLock);
@@ -731,18 +870,26 @@ ChooseExtendedStatisticNameAddition(List *exprs)
buf[0] = '\0';
foreach(lc, exprs)
{
- ColumnRef *cref = (ColumnRef *) lfirst(lc);
+ StatsElem *selem = (StatsElem *) lfirst(lc);
const char *name;
/* It should be one of these, but just skip if it happens not to be */
- if (!IsA(cref, ColumnRef))
+ if (!IsA(selem, StatsElem))
continue;
- name = strVal((Value *) linitial(cref->fields));
+ name = selem->name;
if (buflen > 0)
buf[buflen++] = '_'; /* insert _ between names */
+ /*
+ * FIXME use 'expr' for expressions, which have empty column names.
+ * For indexes this is handled in ChooseIndexColumnNames, but we
+ * have no such function for stats.
+ */
+ if (!name)
+ name = "expr";
+
/*
* At this point we have buflen <= NAMEDATALEN. name should be less
* than NAMEDATALEN already, but use strlcpy for paranoia.
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index ba3ccc712c..a21be7ffb1 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2925,6 +2925,17 @@ _copyIndexElem(const IndexElem *from)
return newnode;
}
+static StatsElem *
+_copyStatsElem(const StatsElem *from)
+{
+ StatsElem *newnode = makeNode(StatsElem);
+
+ COPY_STRING_FIELD(name);
+ COPY_NODE_FIELD(expr);
+
+ return newnode;
+}
+
static ColumnDef *
_copyColumnDef(const ColumnDef *from)
{
@@ -5636,6 +5647,9 @@ copyObjectImpl(const void *from)
case T_IndexElem:
retval = _copyIndexElem(from);
break;
+ case T_StatsElem:
+ retval = _copyStatsElem(from);
+ break;
case T_ColumnDef:
retval = _copyColumnDef(from);
break;
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index a2ef853dc2..2a5421c10f 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -2593,6 +2593,16 @@ _equalIndexElem(const IndexElem *a, const IndexElem *b)
return true;
}
+
+static bool
+_equalStatsElem(const StatsElem *a, const StatsElem *b)
+{
+ COMPARE_STRING_FIELD(name);
+ COMPARE_NODE_FIELD(expr);
+
+ return true;
+}
+
static bool
_equalColumnDef(const ColumnDef *a, const ColumnDef *b)
{
@@ -3689,6 +3699,9 @@ equal(const void *a, const void *b)
case T_IndexElem:
retval = _equalIndexElem(a, b);
break;
+ case T_StatsElem:
+ retval = _equalStatsElem(a, b);
+ break;
case T_ColumnDef:
retval = _equalColumnDef(a, b);
break;
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 8392be6d44..956e8d8151 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2932,6 +2932,15 @@ _outIndexElem(StringInfo str, const IndexElem *node)
WRITE_ENUM_FIELD(nulls_ordering, SortByNulls);
}
+static void
+_outStatsElem(StringInfo str, const StatsElem *node)
+{
+ WRITE_NODE_TYPE("STATSELEM");
+
+ WRITE_STRING_FIELD(name);
+ WRITE_NODE_FIELD(expr);
+}
+
static void
_outQuery(StringInfo str, const Query *node)
{
@@ -4241,6 +4250,9 @@ outNode(StringInfo str, const void *obj)
case T_IndexElem:
_outIndexElem(str, obj);
break;
+ case T_StatsElem:
+ _outStatsElem(str, obj);
+ break;
case T_Query:
_outQuery(str, obj);
break;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index da322b453e..1e64d52c83 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -34,6 +34,7 @@
#include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
#include "nodes/supportnodes.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
@@ -1302,6 +1303,7 @@ get_relation_constraints(PlannerInfo *root,
static List *
get_relation_statistics(RelOptInfo *rel, Relation relation)
{
+ Index varno = rel->relid;
List *statoidlist;
List *stainfos = NIL;
ListCell *l;
@@ -1316,6 +1318,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
HeapTuple dtup;
Bitmapset *keys = NULL;
int i;
+ List *exprs = NIL;
htup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statOid));
if (!HeapTupleIsValid(htup))
@@ -1334,6 +1337,49 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
for (i = 0; i < staForm->stxkeys.dim1; i++)
keys = bms_add_member(keys, staForm->stxkeys.values[i]);
+ /*
+ * preprocess expression (if any)
+ *
+ * FIXME Should we cache the result somewhere?
+ */
+ {
+ bool isnull;
+ Datum datum;
+
+ /* decode expression (if any) */
+ datum = SysCacheGetAttr(STATEXTOID, htup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ if (!isnull)
+ {
+ char *exprsString;
+
+ exprsString = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(exprsString);
+ pfree(exprsString);
+
+ /*
+ * Run the expressions through eval_const_expressions. This is not just an
+ * optimization, but is necessary, because the planner will be comparing
+ * them to similarly-processed qual clauses, and may fail to detect valid
+ * matches without this. We must not use canonicalize_qual, however,
+ * since these aren't qual expressions.
+ */
+ exprs = (List *) eval_const_expressions(NULL, (Node *) exprs);
+
+ /* May as well fix opfuncids too */
+ fix_opfuncids((Node *) exprs);
+
+ /*
+ * Modify the copies we obtain from the relcache to have the
+ * correct varno for the parent relation, so that they match up
+ * correctly against qual clauses.
+ */
+ if (varno != 1)
+ ChangeVarNodes((Node *) exprs, 1, varno, 0);
+ }
+ }
+
/* add one StatisticExtInfo for each kind built */
if (statext_is_kind_built(dtup, STATS_EXT_NDISTINCT))
{
@@ -1343,6 +1389,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
info->rel = rel;
info->kind = STATS_EXT_NDISTINCT;
info->keys = bms_copy(keys);
+ info->exprs = exprs;
stainfos = lappend(stainfos, info);
}
@@ -1355,6 +1402,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
info->rel = rel;
info->kind = STATS_EXT_DEPENDENCIES;
info->keys = bms_copy(keys);
+ info->exprs = exprs;
stainfos = lappend(stainfos, info);
}
@@ -1367,6 +1415,20 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
info->rel = rel;
info->kind = STATS_EXT_MCV;
info->keys = bms_copy(keys);
+ info->exprs = exprs;
+
+ stainfos = lappend(stainfos, info);
+ }
+
+ if (statext_is_kind_built(dtup, STATS_EXT_EXPRESSIONS))
+ {
+ StatisticExtInfo *info = makeNode(StatisticExtInfo);
+
+ info->statOid = statOid;
+ info->rel = rel;
+ info->kind = STATS_EXT_EXPRESSIONS;
+ info->keys = bms_copy(keys);
+ info->exprs = exprs;
stainfos = lappend(stainfos, info);
}
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 31c95443a5..d219976b53 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -232,6 +232,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
WindowDef *windef;
JoinExpr *jexpr;
IndexElem *ielem;
+ StatsElem *selem;
Alias *alias;
RangeVar *range;
IntoClause *into;
@@ -396,7 +397,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
old_aggr_definition old_aggr_list
oper_argtypes RuleActionList RuleActionMulti
opt_column_list columnList opt_name_list
- sort_clause opt_sort_clause sortby_list index_params
+ sort_clause opt_sort_clause sortby_list index_params stats_params
opt_include opt_c_include index_including_params
name_list role_list from_clause from_list opt_array_bounds
qualified_name_list any_name any_name_list type_name_list
@@ -500,6 +501,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type <list> func_alias_clause
%type <sortby> sortby
%type <ielem> index_elem index_elem_options
+%type <selem> stats_param
%type <node> table_ref
%type <jexpr> joined_table
%type <range> relation_expr
@@ -4049,7 +4051,7 @@ ExistingIndex: USING INDEX name { $$ = $3; }
CreateStatsStmt:
CREATE STATISTICS any_name
- opt_name_list ON expr_list FROM from_list
+ opt_name_list ON stats_params FROM from_list
{
CreateStatsStmt *n = makeNode(CreateStatsStmt);
n->defnames = $3;
@@ -4061,7 +4063,7 @@ CreateStatsStmt:
$$ = (Node *)n;
}
| CREATE STATISTICS IF_P NOT EXISTS any_name
- opt_name_list ON expr_list FROM from_list
+ opt_name_list ON stats_params FROM from_list
{
CreateStatsStmt *n = makeNode(CreateStatsStmt);
n->defnames = $6;
@@ -4074,6 +4076,36 @@ CreateStatsStmt:
}
;
+/*
+ * Statistics attributes can be either simple column references, or arbitrary
+ * expressions in parens. For compatibility with index attributes permitted
+ * in CREATE INDEX, we allow an expression that's just a function call to be
+ * written without parens.
+ */
+
+stats_params: stats_param { $$ = list_make1($1); }
+ | stats_params ',' stats_param { $$ = lappend($1, $3); }
+ ;
+
+stats_param: ColId
+ {
+ $$ = makeNode(StatsElem);
+ $$->name = $1;
+ $$->expr = NULL;
+ }
+ | func_expr_windowless
+ {
+ $$ = makeNode(StatsElem);
+ $$->name = NULL;
+ $$->expr = $1;
+ }
+ | '(' a_expr ')'
+ {
+ $$ = makeNode(StatsElem);
+ $$->name = NULL;
+ $$->expr = $2;
+ }
+ ;
/*****************************************************************************
*
diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index 588f005dd9..0b0841afb9 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -484,6 +484,13 @@ check_agglevels_and_constraints(ParseState *pstate, Node *expr)
else
err = _("grouping operations are not allowed in index predicates");
+ break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ if (isAgg)
+ err = _("aggregate functions are not allowed in statistics expressions");
+ else
+ err = _("grouping operations are not allowed in statistics expressions");
+
break;
case EXPR_KIND_ALTER_COL_TRANSFORM:
if (isAgg)
@@ -906,6 +913,9 @@ transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc,
case EXPR_KIND_INDEX_EXPRESSION:
err = _("window functions are not allowed in index expressions");
break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ err = _("window functions are not allowed in statistics expressions");
+ break;
case EXPR_KIND_INDEX_PREDICATE:
err = _("window functions are not allowed in index predicates");
break;
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 379355f9bf..fcc1bb33d1 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -500,6 +500,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
case EXPR_KIND_FUNCTION_DEFAULT:
case EXPR_KIND_INDEX_EXPRESSION:
case EXPR_KIND_INDEX_PREDICATE:
+ case EXPR_KIND_STATS_EXPRESSION:
case EXPR_KIND_ALTER_COL_TRANSFORM:
case EXPR_KIND_EXECUTE_PARAMETER:
case EXPR_KIND_TRIGGER_WHEN:
@@ -1739,6 +1740,9 @@ transformSubLink(ParseState *pstate, SubLink *sublink)
case EXPR_KIND_INDEX_PREDICATE:
err = _("cannot use subquery in index predicate");
break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ err = _("cannot use subquery in statistics expression");
+ break;
case EXPR_KIND_ALTER_COL_TRANSFORM:
err = _("cannot use subquery in transform expression");
break;
@@ -3028,6 +3032,8 @@ ParseExprKindName(ParseExprKind exprKind)
return "index expression";
case EXPR_KIND_INDEX_PREDICATE:
return "index predicate";
+ case EXPR_KIND_STATS_EXPRESSION:
+ return "statistics expression";
case EXPR_KIND_ALTER_COL_TRANSFORM:
return "USING";
case EXPR_KIND_EXECUTE_PARAMETER:
diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 07d0013e84..652930ddf9 100644
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -2503,6 +2503,9 @@ check_srf_call_placement(ParseState *pstate, Node *last_srf, int location)
case EXPR_KIND_INDEX_PREDICATE:
err = _("set-returning functions are not allowed in index predicates");
break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ err = _("set-returning functions are not allowed in statistics expressions");
+ break;
case EXPR_KIND_ALTER_COL_TRANSFORM:
err = _("set-returning functions are not allowed in transform expressions");
break;
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index b31f3afa03..0028240d1a 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -1898,6 +1898,9 @@ generateClonedExtStatsStmt(RangeVar *heapRel, Oid heapRelid,
stat_types = lappend(stat_types, makeString("dependencies"));
else if (enabled[i] == STATS_EXT_MCV)
stat_types = lappend(stat_types, makeString("mcv"));
+ else if (enabled[i] == STATS_EXT_EXPRESSIONS)
+ /* expression stats are not exposed to users */
+ continue;
else
elog(ERROR, "unrecognized statistics kind %c", enabled[i]);
}
@@ -1905,14 +1908,43 @@ generateClonedExtStatsStmt(RangeVar *heapRel, Oid heapRelid,
/* Determine which columns the statistics are on */
for (i = 0; i < statsrec->stxkeys.dim1; i++)
{
- ColumnRef *cref = makeNode(ColumnRef);
+ StatsElem *selem = makeNode(StatsElem);
AttrNumber attnum = statsrec->stxkeys.values[i];
- cref->fields = list_make1(makeString(get_attname(heapRelid,
- attnum, false)));
- cref->location = -1;
+ selem->name = get_attname(heapRelid, attnum, false);
+ selem->expr = NULL;
- def_names = lappend(def_names, cref);
+ def_names = lappend(def_names, selem);
+ }
+
+ /*
+ * Now handle expressions, if there are any. The order does not
+ * matter for extended stats, so we simply append them after
+ * simple column references.
+ */
+ datum = SysCacheGetAttr(STATEXTOID, ht_stats,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ if (!isnull)
+ {
+ ListCell *lc;
+ List *exprs = NIL;
+ char *exprsString;
+
+ exprsString = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(exprsString);
+
+ foreach(lc, exprs)
+ {
+ StatsElem *selem = makeNode(StatsElem);
+
+ selem->name = NULL;
+ selem->expr = (Node *) lfirst(lc);
+
+ def_names = lappend(def_names, selem);
+ }
+
+ pfree(exprsString);
}
/* finally, build the output node */
@@ -1923,6 +1955,7 @@ generateClonedExtStatsStmt(RangeVar *heapRel, Oid heapRelid,
stats->relations = list_make1(heapRel);
stats->stxcomment = NULL;
stats->if_not_exists = false;
+ stats->transformed = true; /* don't need transformStatsStmt */
/* Clean up */
ReleaseSysCache(ht_stats);
@@ -2847,6 +2880,84 @@ transformIndexStmt(Oid relid, IndexStmt *stmt, const char *queryString)
return stmt;
}
+/*
+ * transformStatsStmt - parse analysis for CREATE STATISTICS
+ *
+ * To avoid race conditions, it's important that this function rely only on
+ * the passed-in relid (and not on stmt->relation) to determine the target
+ * relation.
+ */
+CreateStatsStmt *
+transformStatsStmt(Oid relid, CreateStatsStmt *stmt, const char *queryString)
+{
+ ParseState *pstate;
+ ParseNamespaceItem *nsitem;
+ ListCell *l;
+ Relation rel;
+
+ /* Nothing to do if statement already transformed. */
+ if (stmt->transformed)
+ return stmt;
+
+ /*
+ * We must not scribble on the passed-in CreateStatsStmt, so copy it. (This is
+ * overkill, but easy.)
+ */
+ stmt = copyObject(stmt);
+
+ /* Set up pstate */
+ pstate = make_parsestate(NULL);
+ pstate->p_sourcetext = queryString;
+
+ /*
+ * Put the parent table into the rtable so that the expressions can refer
+ * to its fields without qualification. Caller is responsible for locking
+ * relation, but we still need to open it.
+ */
+ rel = relation_open(relid, NoLock);
+ nsitem = addRangeTableEntryForRelation(pstate, rel,
+ AccessShareLock,
+ NULL, false, true);
+
+ /* no to join list, yes to namespaces */
+ addNSItemToQuery(pstate, nsitem, false, true, true);
+
+ /* take care of any expressions */
+ foreach(l, stmt->exprs)
+ {
+ StatsElem *selem = (StatsElem *) lfirst(l);
+
+ if (selem->expr)
+ {
+ /* Now do parse transformation of the expression */
+ selem->expr = transformExpr(pstate, selem->expr,
+ EXPR_KIND_STATS_EXPRESSION);
+
+ /* We have to fix its collations too */
+ assign_expr_collations(pstate, selem->expr);
+ }
+ }
+
+ /*
+ * Check that only the base rel is mentioned. (This should be dead code
+ * now that add_missing_from is history.)
+ */
+ if (list_length(pstate->p_rtable) != 1)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+ errmsg("statistics expressions and predicates can refer only to the table being indexed")));
+
+ free_parsestate(pstate);
+
+ /* Close relation */
+ table_close(rel, NoLock);
+
+ /* Mark statement as successfully transformed */
+ stmt->transformed = true;
+
+ return stmt;
+}
+
/*
* transformRuleStmt -
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index f6e399b192..6bf3127bcc 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -70,15 +70,18 @@ static void generate_dependencies(DependencyGenerator state);
static DependencyGenerator DependencyGenerator_init(int n, int k);
static void DependencyGenerator_free(DependencyGenerator state);
static AttrNumber *DependencyGenerator_next(DependencyGenerator state);
-static double dependency_degree(int numrows, HeapTuple *rows, int k,
- AttrNumber *dependency, VacAttrStats **stats, Bitmapset *attrs);
+static double dependency_degree(int numrows, HeapTuple *rows,
+ ExprInfo *exprs, int k,
+ AttrNumber *dependency, VacAttrStats **stats,
+ Bitmapset *attrs);
static bool dependency_is_fully_matched(MVDependency *dependency,
Bitmapset *attnums);
static bool dependency_is_compatible_clause(Node *clause, Index relid,
AttrNumber *attnum);
+static bool dependency_is_compatible_expression(Node *clause, Index relid,
+ List *statlist, Node **expr);
static MVDependency *find_strongest_dependency(MVDependencies **dependencies,
- int ndependencies,
- Bitmapset *attnums);
+ int ndependencies, Bitmapset *attnums);
static Selectivity clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
int varRelid, JoinType jointype,
SpecialJoinInfo *sjinfo,
@@ -219,8 +222,9 @@ DependencyGenerator_next(DependencyGenerator state)
* the last one.
*/
static double
-dependency_degree(int numrows, HeapTuple *rows, int k, AttrNumber *dependency,
- VacAttrStats **stats, Bitmapset *attrs)
+dependency_degree(int numrows, HeapTuple *rows, ExprInfo *exprs, int k,
+ AttrNumber *dependency, VacAttrStats **stats,
+ Bitmapset *attrs)
{
int i,
nitems;
@@ -289,8 +293,8 @@ dependency_degree(int numrows, HeapTuple *rows, int k, AttrNumber *dependency,
* descriptor. For now that assumption holds, but it might change in the
* future for example if we support statistics on multiple tables.
*/
- items = build_sorted_items(numrows, &nitems, rows, stats[0]->tupDesc,
- mss, k, attnums_dep);
+ items = build_sorted_items(numrows, &nitems, rows, exprs,
+ stats[0]->tupDesc, mss, k, attnums_dep);
/*
* Walk through the sorted array, split it into rows according to the
@@ -360,7 +364,8 @@ dependency_degree(int numrows, HeapTuple *rows, int k, AttrNumber *dependency,
* (c) -> b
*/
MVDependencies *
-statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
+statext_dependencies_build(int numrows, HeapTuple *rows,
+ ExprInfo *exprs, Bitmapset *attrs,
VacAttrStats **stats)
{
int i,
@@ -371,6 +376,9 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
/* result */
MVDependencies *dependencies = NULL;
+ /* treat expressions as special attributes with high attnums */
+ attrs = add_expressions_to_attributes(attrs, exprs->nexprs);
+
/*
* Transform the bms into an array, to make accessing i-th member easier.
*/
@@ -398,7 +406,8 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
MVDependency *d;
/* compute how valid the dependency seems */
- degree = dependency_degree(numrows, rows, k, dependency, stats, attrs);
+ degree = dependency_degree(numrows, rows, exprs, k, dependency,
+ stats, attrs);
/*
* if the dependency seems entirely invalid, don't store it
@@ -441,6 +450,8 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
DependencyGenerator_free(DependencyGenerator);
}
+ pfree(attrs);
+
return dependencies;
}
@@ -639,7 +650,7 @@ statext_dependencies_load(Oid mvoid)
Anum_pg_statistic_ext_data_stxddependencies, &isnull);
if (isnull)
elog(ERROR,
- "requested statistic kind \"%c\" is not yet built for statistics object %u",
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
STATS_EXT_DEPENDENCIES, mvoid);
result = statext_dependencies_deserialize(DatumGetByteaPP(deps));
@@ -1157,6 +1168,134 @@ clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
return s1;
}
+/*
+ * dependency_is_compatible_expression
+ * Determines if the expression is compatible with functional dependencies
+ *
+ * Similar to dependency_is_compatible_clause, but doesn't enforce that the
+ * expression is a simple Var. OTOH we check that there's at least one
+ * statistics object matching the expression.
+ */
+static bool
+dependency_is_compatible_expression(Node *clause, Index relid, List *statlist, Node **expr)
+{
+ List *vars;
+ ListCell *lc, *lc2;
+
+ RestrictInfo *rinfo = (RestrictInfo *) clause;
+ Node *clause_expr;
+
+ if (!IsA(rinfo, RestrictInfo))
+ return false;
+
+ /* Pseudoconstants are not interesting (they couldn't contain a Var) */
+ if (rinfo->pseudoconstant)
+ return false;
+
+ /* Clauses referencing multiple, or no, varnos are incompatible */
+ if (bms_membership(rinfo->clause_relids) != BMS_SINGLETON)
+ return false;
+
+ if (is_opclause(rinfo->clause))
+ {
+ /* If it's an opclause, check for Var = Const or Const = Var. */
+ OpExpr *expr = (OpExpr *) rinfo->clause;
+
+ /* Only expressions with two arguments are candidates. */
+ if (list_length(expr->args) != 2)
+ return false;
+
+ /* Make sure non-selected argument is a pseudoconstant. */
+ if (is_pseudo_constant_clause(lsecond(expr->args)))
+ clause_expr = linitial(expr->args);
+ else if (is_pseudo_constant_clause(linitial(expr->args)))
+ clause_expr = lsecond(expr->args);
+ else
+ return false;
+
+ /*
+ * If it's not an "=" operator, just ignore the clause, as it's not
+ * compatible with functional dependencies.
+ *
+ * This uses the function for estimating selectivity, not the operator
+ * directly (a bit awkward, but well ...).
+ *
+ * XXX this is pretty dubious; probably it'd be better to check btree
+ * or hash opclass membership, so as not to be fooled by custom
+ * selectivity functions, and to be more consistent with decisions
+ * elsewhere in the planner.
+ */
+ if (get_oprrest(expr->opno) != F_EQSEL)
+ return false;
+
+ /* OK to proceed with checking "var" */
+ }
+ else if (is_notclause(rinfo->clause))
+ {
+ /*
+ * "NOT x" can be interpreted as "x = false", so get the argument and
+ * proceed with seeing if it's a suitable Var.
+ */
+ clause_expr = (Node *) get_notclausearg(rinfo->clause);
+ }
+ else
+ {
+ /*
+ * A boolean expression "x" can be interpreted as "x = true", so
+ * proceed with seeing if it's a suitable Var.
+ */
+ clause_expr = (Node *) rinfo->clause;
+ }
+
+ /*
+ * We may ignore any RelabelType node above the operand. (There won't be
+ * more than one, since eval_const_expressions has been applied already.)
+ */
+ if (IsA(clause_expr, RelabelType))
+ clause_expr = (Node *) ((RelabelType *) clause_expr)->arg;
+
+ vars = pull_var_clause(clause_expr, 0);
+
+ foreach (lc, vars)
+ {
+ Var *var = (Var *) lfirst(lc);
+
+ /* Ensure Var is from the correct relation */
+ if (var->varno != relid)
+ return false;
+
+ /* We also better ensure the Var is from the current level */
+ if (var->varlevelsup != 0)
+ return false;
+
+ /* Also ignore system attributes (we don't allow stats on those) */
+ if (!AttrNumberIsForUserDefinedAttr(var->varattno))
+ return false;
+ }
+
+ foreach (lc, statlist)
+ {
+ StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
+
+ /* ignore stats without dependencies */
+ if (info->kind != STATS_EXT_DEPENDENCIES)
+ continue;
+
+ foreach (lc2, info->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(clause_expr, stat_expr))
+ {
+ *expr = stat_expr;
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
/*
* dependencies_clauselist_selectivity
* Return the estimated selectivity of (a subset of) the given clauses
@@ -1205,6 +1344,10 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
int ndependencies;
int i;
+ /* unique expressions */
+ Node **unique_exprs;
+ int unique_exprs_cnt;
+
/* check if there's any stats that might be useful for us. */
if (!has_stats_of_kind(rel->statlist, STATS_EXT_DEPENDENCIES))
return 1.0;
@@ -1212,6 +1355,14 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
list_attnums = (AttrNumber *) palloc(sizeof(AttrNumber) *
list_length(clauses));
+ /*
+ * We allocate space as if every clause was a unique expression, although
+ * that's probably overkill. Some will be simple column references that
+ * we'll translate to attnums, and there might be duplicates.
+ */
+ unique_exprs = (Node **) palloc(sizeof(Node *) * list_length(clauses));
+ unique_exprs_cnt = 0;
+
/*
* Pre-process the clauses list to extract the attnums seen in each item.
* We need to determine if there's any clauses which will be useful for
@@ -1222,29 +1373,76 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
*
* We also skip clauses that we already estimated using different types of
* statistics (we treat them as incompatible).
+ *
+ * For expressions, we generate attnums higher than MaxHeapAttributeNumber
+ * so that we can work with attnums only.
*/
listidx = 0;
foreach(l, clauses)
{
Node *clause = (Node *) lfirst(l);
AttrNumber attnum;
+ Node *expr = NULL;
- if (!bms_is_member(listidx, *estimatedclauses) &&
- dependency_is_compatible_clause(clause, rel->relid, &attnum))
+ /* ignore clause by default */
+ list_attnums[listidx] = InvalidAttrNumber;
+
+ if (!bms_is_member(listidx, *estimatedclauses))
{
- list_attnums[listidx] = attnum;
- clauses_attnums = bms_add_member(clauses_attnums, attnum);
+ /*
+ * If it's a simple column refrence, just extract the attnum. If
+ * it's an expression, make sure it's not a duplicate and assign
+ * a special attnum to it (higher than any regular value).
+ */
+ if (dependency_is_compatible_clause(clause, rel->relid, &attnum))
+ {
+ list_attnums[listidx] = attnum;
+ clauses_attnums = bms_add_member(clauses_attnums, attnum);
+ }
+ else if (dependency_is_compatible_expression(clause, rel->relid,
+ rel->statlist,
+ &expr))
+ {
+ /* special attnum assigned to this expression */
+ attnum = InvalidAttrNumber;
+
+ Assert(expr != NULL);
+
+ /* If the expression is duplicate, use the same attnum. */
+ for (i = 0; i < unique_exprs_cnt; i++)
+ {
+ if (equal(unique_exprs[i], expr))
+ {
+ attnum = EXPRESSION_ATTNUM(i);
+ break;
+ }
+ }
+
+ /* not found in the list, so add it */
+ if (attnum == InvalidAttrNumber)
+ {
+ attnum = EXPRESSION_ATTNUM(unique_exprs_cnt);
+ unique_exprs[unique_exprs_cnt++] = expr;
+
+ /* shouldn't have seen this attnum yet */
+ Assert(!bms_is_member(attnum, clauses_attnums));
+
+ /* we may add the attnum repeatedly to clauses_attnums */
+ clauses_attnums = bms_add_member(clauses_attnums, attnum);
+ }
+
+ /* remember which attnum was assigned to this clause */
+ list_attnums[listidx] = attnum;
+ }
}
- else
- list_attnums[listidx] = InvalidAttrNumber;
listidx++;
}
/*
- * If there's not at least two distinct attnums then reject the whole list
- * of clauses. We must return 1.0 so the calling function's selectivity is
- * unaffected.
+ * If there's not at least two distinct attnums and expressions, then
+ * reject the whole list of clauses. We must return 1.0 so the calling
+ * function's selectivity is unaffected.
*/
if (bms_membership(clauses_attnums) != BMS_MULTIPLE)
{
@@ -1273,25 +1471,138 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
{
StatisticExtInfo *stat = (StatisticExtInfo *) lfirst(l);
Bitmapset *matched;
- BMS_Membership membership;
+ int nmatched;
+ int nexprs;
+ MVDependencies *deps;
/* skip statistics that are not of the correct type */
if (stat->kind != STATS_EXT_DEPENDENCIES)
continue;
+ /* count matching simple clauses */
matched = bms_intersect(clauses_attnums, stat->keys);
- membership = bms_membership(matched);
+ nmatched = bms_num_members(matched);
bms_free(matched);
- /* skip objects matching fewer than two attributes from clauses */
- if (membership != BMS_MULTIPLE)
+ /* count matching expressions */
+ nexprs = 0;
+ for (i = 0; i < unique_exprs_cnt; i++)
+ {
+ ListCell *lc;
+
+ foreach (lc, stat->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ /* try to match it */
+ if (equal(stat_expr, unique_exprs[i]))
+ nexprs++;
+ }
+ }
+
+ /*
+ * Skip objects matching fewer than two attributes/expressions
+ * from clauses.
+ */
+ if (nmatched + nexprs < 2)
continue;
- func_dependencies[nfunc_dependencies]
- = statext_dependencies_load(stat->statOid);
+ deps = statext_dependencies_load(stat->statOid);
- total_ndeps += func_dependencies[nfunc_dependencies]->ndeps;
- nfunc_dependencies++;
+ /*
+ * The expressions may be represented by different attnums in the
+ * stats, we need to remap them to be consistent with the clauses.
+ * That will make the later steps (e.g. picking the strongest item
+ * and so on) much simpler.
+ *
+ * When we're at it, we can also remove dependencies referencing
+ * missing clauses (i.e. expressions that are not in the clauses).
+ *
+ * XXX We might also skip clauses referencing missing attnums, not
+ * just expressions.
+ */
+ if (stat->exprs)
+ {
+ int ndeps = 0;
+
+ for (i = 0; i < deps->ndeps; i++)
+ {
+ bool skip = false;
+ MVDependency *dep = deps->deps[i];
+ int j;
+
+ for (j = 0; j < dep->nattributes; j++)
+ {
+ int idx;
+ Node *expr;
+ int k;
+ AttrNumber unique_attnum = InvalidAttrNumber;
+
+ /* regular attribute, no need to remap */
+ if (dep->attributes[j] <= MaxHeapAttributeNumber)
+ continue;
+
+ /* index of the expression */
+ idx = EXPRESSION_INDEX(dep->attributes[j]);
+
+ /* make sure the expression index is valid */
+ Assert((idx >= 0) && (idx < list_length(stat->exprs)));
+
+ expr = (Node *) list_nth(stat->exprs, idx);
+
+ /* try to find the expression in the unique list */
+ for (k = 0; k < unique_exprs_cnt; k++)
+ {
+ /*
+ * found a matching unique expression, use the attnum
+ * (derived from index of the unique expression)
+ */
+ if (equal(unique_exprs[k], expr))
+ {
+ unique_attnum = EXPRESSION_ATTNUM(k);
+ break;
+ }
+ }
+
+ /*
+ * Not found a matching expression, so we can simply
+ * skip this dependency, because there's no chance it
+ * will be fully covered.
+ */
+ if (unique_attnum == InvalidAttrNumber)
+ {
+ skip = true;
+ break;
+ }
+
+ /* otherwise remap it to the new attnum */
+ dep->attributes[j] = unique_attnum;
+ }
+
+ /* if found a matching, */
+ if (!skip)
+ {
+ /* maybe we've skipped something earlier, so move it */
+ if (ndeps != i)
+ deps->deps[ndeps] = deps->deps[i];
+
+ ndeps++;
+ }
+ }
+
+ deps->ndeps = ndeps;
+ }
+
+ /*
+ * It's possible we've removed all dependencies, in which case we
+ * don't bother adding it to the list.
+ */
+ if (deps->ndeps > 0)
+ {
+ func_dependencies[nfunc_dependencies] = deps;
+ total_ndeps += deps->ndeps;
+ nfunc_dependencies++;
+ }
}
/* if no matching stats could be found then we've nothing to do */
@@ -1300,6 +1611,7 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
pfree(func_dependencies);
bms_free(clauses_attnums);
pfree(list_attnums);
+ pfree(unique_exprs);
return 1.0;
}
@@ -1347,6 +1659,7 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
pfree(func_dependencies);
bms_free(clauses_attnums);
pfree(list_attnums);
+ pfree(unique_exprs);
return s1;
}
diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index a030ea3653..fd6e160ff4 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -24,6 +24,7 @@
#include "catalog/pg_collation.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
+#include "executor/executor.h"
#include "commands/progress.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
@@ -35,13 +36,16 @@
#include "statistics/statistics.h"
#include "utils/acl.h"
#include "utils/array.h"
+#include "utils/attoptcache.h"
#include "utils/builtins.h"
+#include "utils/datum.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/selfuncs.h"
#include "utils/syscache.h"
+#include "utils/typcache.h"
/*
* To avoid consuming too much memory during analysis and/or too much space
@@ -64,20 +68,37 @@ typedef struct StatExtEntry
char *schema; /* statistics object's schema */
char *name; /* statistics object's name */
Bitmapset *columns; /* attribute numbers covered by the object */
- List *types; /* 'char' list of enabled statistic kinds */
+ List *types; /* 'char' list of enabled statistics kinds */
int stattarget; /* statistics target (-1 for default) */
+ List *exprs; /* expressions */
} StatExtEntry;
static List *fetch_statentries_for_relation(Relation pg_statext, Oid relid);
-static VacAttrStats **lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
+static VacAttrStats **lookup_var_attr_stats(Relation rel, Bitmapset *attrs, List *exprs,
int nvacatts, VacAttrStats **vacatts);
-static void statext_store(Oid relid,
+static void statext_store(Oid statOid,
MVNDistinct *ndistinct, MVDependencies *dependencies,
- MCVList *mcv, VacAttrStats **stats);
+ MCVList *mcv, Datum exprs, VacAttrStats **stats);
static int statext_compute_stattarget(int stattarget,
int natts, VacAttrStats **stats);
+typedef struct AnlExprData
+{
+ Node *expr; /* expression to analyze */
+ VacAttrStats *vacattrstat; /* index attrs to analyze */
+} AnlExprData;
+
+static void compute_expr_stats(Relation onerel, double totalrows,
+ AnlExprData *exprdata, int nexprs,
+ HeapTuple *rows, int numrows);
+static Datum serialize_expr_stats(AnlExprData *exprdata, int nexprs);
+static Datum expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
+static AnlExprData *build_expr_data(List *exprs);
+static VacAttrStats *examine_expression(Node *expr);
+static ExprInfo *evaluate_expressions(Relation rel, List *exprs,
+ int numrows, HeapTuple *rows);
+
/*
* Compute requested extended stats, using the rows sampled for the plain
* (single-column) stats.
@@ -92,7 +113,7 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
{
Relation pg_stext;
ListCell *lc;
- List *stats;
+ List *statslist;
MemoryContext cxt;
MemoryContext oldcxt;
int64 ext_cnt;
@@ -103,10 +124,10 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
oldcxt = MemoryContextSwitchTo(cxt);
pg_stext = table_open(StatisticExtRelationId, RowExclusiveLock);
- stats = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
+ statslist = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
/* report this phase */
- if (stats != NIL)
+ if (statslist != NIL)
{
const int index[] = {
PROGRESS_ANALYZE_PHASE,
@@ -114,28 +135,30 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
};
const int64 val[] = {
PROGRESS_ANALYZE_PHASE_COMPUTE_EXT_STATS,
- list_length(stats)
+ list_length(statslist)
};
pgstat_progress_update_multi_param(2, index, val);
}
ext_cnt = 0;
- foreach(lc, stats)
+ foreach(lc, statslist)
{
StatExtEntry *stat = (StatExtEntry *) lfirst(lc);
MVNDistinct *ndistinct = NULL;
MVDependencies *dependencies = NULL;
MCVList *mcv = NULL;
+ Datum exprstats = (Datum) 0;
VacAttrStats **stats;
ListCell *lc2;
int stattarget;
+ ExprInfo *exprs;
/*
* Check if we can build these stats based on the column analyzed. If
* not, report this fact (except in autovacuum) and move on.
*/
- stats = lookup_var_attr_stats(onerel, stat->columns,
+ stats = lookup_var_attr_stats(onerel, stat->columns, stat->exprs,
natts, vacattrstats);
if (!stats)
{
@@ -150,10 +173,6 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
continue;
}
- /* check allowed number of dimensions */
- Assert(bms_num_members(stat->columns) >= 2 &&
- bms_num_members(stat->columns) <= STATS_MAX_DIMENSIONS);
-
/* compute statistics target for this statistics */
stattarget = statext_compute_stattarget(stat->stattarget,
bms_num_members(stat->columns),
@@ -167,6 +186,9 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
if (stattarget == 0)
continue;
+ /* evaluate expressions (if the statistics has any) */
+ exprs = evaluate_expressions(onerel, stat->exprs, numrows, rows);
+
/* compute statistic of each requested type */
foreach(lc2, stat->types)
{
@@ -174,21 +196,43 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
if (t == STATS_EXT_NDISTINCT)
ndistinct = statext_ndistinct_build(totalrows, numrows, rows,
- stat->columns, stats);
+ exprs, stat->columns,
+ stats);
else if (t == STATS_EXT_DEPENDENCIES)
dependencies = statext_dependencies_build(numrows, rows,
- stat->columns, stats);
+ exprs, stat->columns,
+ stats);
else if (t == STATS_EXT_MCV)
- mcv = statext_mcv_build(numrows, rows, stat->columns, stats,
- totalrows, stattarget);
+ mcv = statext_mcv_build(numrows, rows, exprs, stat->columns,
+ stats, totalrows, stattarget);
+ else if (t == STATS_EXT_EXPRESSIONS)
+ {
+ AnlExprData *exprdata;
+ int nexprs;
+
+ /* should not happen, thanks to checks when defining stats */
+ if (!stat->exprs)
+ elog(ERROR, "requested expression stats, but there are no expressions");
+
+ exprdata = build_expr_data(stat->exprs);
+ nexprs = list_length(stat->exprs);
+
+ compute_expr_stats(onerel, totalrows,
+ exprdata, nexprs,
+ rows, numrows);
+
+ exprstats = serialize_expr_stats(exprdata, nexprs);
+ }
}
/* store the statistics in the catalog */
- statext_store(stat->statOid, ndistinct, dependencies, mcv, stats);
+ statext_store(stat->statOid, ndistinct, dependencies, mcv, exprstats, stats);
/* for reporting progress */
pgstat_progress_update_param(PROGRESS_ANALYZE_EXT_STATS_COMPUTED,
++ext_cnt);
+
+ pfree(exprs);
}
table_close(pg_stext, RowExclusiveLock);
@@ -221,6 +265,13 @@ ComputeExtStatisticsRows(Relation onerel,
MemoryContext oldcxt;
int result = 0;
+ /*
+ * When there are no columns to analyze, just return 0. That's enough
+ * for the callers to not build anything.
+ */
+ if (!natts)
+ return 0;
+
cxt = AllocSetContextCreate(CurrentMemoryContext,
"ComputeExtStatisticsRows",
ALLOCSET_DEFAULT_SIZES);
@@ -241,7 +292,7 @@ ComputeExtStatisticsRows(Relation onerel,
* analyzed. If not, ignore it (don't report anything, we'll do that
* during the actual build BuildRelationExtStatistics).
*/
- stats = lookup_var_attr_stats(onerel, stat->columns,
+ stats = lookup_var_attr_stats(onerel, stat->columns, stat->exprs,
natts, vacattrstats);
if (!stats)
@@ -349,6 +400,10 @@ statext_is_kind_built(HeapTuple htup, char type)
attnum = Anum_pg_statistic_ext_data_stxdmcv;
break;
+ case STATS_EXT_EXPRESSIONS:
+ attnum = Anum_pg_statistic_ext_data_stxdexpr;
+ break;
+
default:
elog(ERROR, "unexpected statistics type requested: %d", type);
}
@@ -388,6 +443,7 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
ArrayType *arr;
char *enabled;
Form_pg_statistic_ext staForm;
+ List *exprs = NIL;
entry = palloc0(sizeof(StatExtEntry));
staForm = (Form_pg_statistic_ext) GETSTRUCT(htup);
@@ -415,10 +471,39 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
{
Assert((enabled[i] == STATS_EXT_NDISTINCT) ||
(enabled[i] == STATS_EXT_DEPENDENCIES) ||
- (enabled[i] == STATS_EXT_MCV));
+ (enabled[i] == STATS_EXT_MCV) ||
+ (enabled[i] == STATS_EXT_EXPRESSIONS));
entry->types = lappend_int(entry->types, (int) enabled[i]);
}
+ /* decode expression (if any) */
+ datum = SysCacheGetAttr(STATEXTOID, htup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ if (!isnull)
+ {
+ char *exprsString;
+
+ exprsString = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(exprsString);
+
+ pfree(exprsString);
+
+ /*
+ * Run the expressions through eval_const_expressions. This is not just an
+ * optimization, but is necessary, because the planner will be comparing
+ * them to similarly-processed qual clauses, and may fail to detect valid
+ * matches without this. We must not use canonicalize_qual, however,
+ * since these aren't qual expressions.
+ */
+ exprs = (List *) eval_const_expressions(NULL, (Node *) exprs);
+
+ /* May as well fix opfuncids too */
+ fix_opfuncids((Node *) exprs);
+ }
+
+ entry->exprs = exprs;
+
result = lappend(result, entry);
}
@@ -427,6 +512,86 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
return result;
}
+
+/*
+ * examine_attribute -- pre-analysis of a single column
+ *
+ * Determine whether the column is analyzable; if so, create and initialize
+ * a VacAttrStats struct for it. If not, return NULL.
+ */
+static VacAttrStats *
+examine_attribute(Node *expr)
+{
+ HeapTuple typtuple;
+ VacAttrStats *stats;
+ int i;
+ bool ok;
+
+ /*
+ * Create the VacAttrStats struct. Note that we only have a copy of the
+ * fixed fields of the pg_attribute tuple.
+ */
+ stats = (VacAttrStats *) palloc0(sizeof(VacAttrStats));
+
+ /* fake the attribute */
+ stats->attr = (Form_pg_attribute) palloc0(ATTRIBUTE_FIXED_PART_SIZE);
+ stats->attr->attstattarget = -1;
+
+ /*
+ * When analyzing an expression index, believe the expression tree's type
+ * not the column datatype --- the latter might be the opckeytype storage
+ * type of the opclass, which is not interesting for our purposes. (Note:
+ * if we did anything with non-expression index columns, we'd need to
+ * figure out where to get the correct type info from, but for now that's
+ * not a problem.) It's not clear whether anyone will care about the
+ * typmod, but we store that too just in case.
+ */
+ stats->attrtypid = exprType(expr);
+ stats->attrtypmod = exprTypmod(expr);
+ stats->attrcollid = exprCollation(expr);
+
+ typtuple = SearchSysCacheCopy1(TYPEOID,
+ ObjectIdGetDatum(stats->attrtypid));
+ if (!HeapTupleIsValid(typtuple))
+ elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
+ stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
+ // stats->anl_context = anl_context; /* FIXME? */
+ stats->tupattnum = InvalidAttrNumber;
+
+ /*
+ * The fields describing the stats->stavalues[n] element types default to
+ * the type of the data being analyzed, but the type-specific typanalyze
+ * function can change them if it wants to store something else.
+ */
+ for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
+ {
+ stats->statypid[i] = stats->attrtypid;
+ stats->statyplen[i] = stats->attrtype->typlen;
+ stats->statypbyval[i] = stats->attrtype->typbyval;
+ stats->statypalign[i] = stats->attrtype->typalign;
+ }
+
+ /*
+ * Call the type-specific typanalyze function. If none is specified, use
+ * std_typanalyze().
+ */
+ if (OidIsValid(stats->attrtype->typanalyze))
+ ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
+ PointerGetDatum(stats)));
+ else
+ ok = std_typanalyze(stats);
+
+ if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
+ {
+ heap_freetuple(typtuple);
+ pfree(stats->attr);
+ pfree(stats);
+ return NULL;
+ }
+
+ return stats;
+}
+
/*
* Using 'vacatts' of size 'nvacatts' as input data, return a newly built
* VacAttrStats array which includes only the items corresponding to
@@ -435,15 +600,18 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
* to the caller that the stats should not be built.
*/
static VacAttrStats **
-lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
+lookup_var_attr_stats(Relation rel, Bitmapset *attrs, List *exprs,
int nvacatts, VacAttrStats **vacatts)
{
int i = 0;
int x = -1;
+ int natts;
VacAttrStats **stats;
+ ListCell *lc;
- stats = (VacAttrStats **)
- palloc(bms_num_members(attrs) * sizeof(VacAttrStats *));
+ natts = bms_num_members(attrs) + list_length(exprs);
+
+ stats = (VacAttrStats **) palloc(natts * sizeof(VacAttrStats *));
/* lookup VacAttrStats info for the requested columns (same attnum) */
while ((x = bms_next_member(attrs, x)) >= 0)
@@ -480,6 +648,24 @@ lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
i++;
}
+ /* also add info for expressions */
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+
+ stats[i] = examine_attribute(expr);
+
+ /*
+ * FIXME We need tuple descriptor later, and we just grab it from
+ * stats[0]->tupDesc (see e.g. statext_mcv_build). But as coded
+ * examine_attribute does not set that, so just grab it from the
+ * first vacatts element.
+ */
+ stats[i]->tupDesc = vacatts[0]->tupDesc;
+
+ i++;
+ }
+
return stats;
}
@@ -491,7 +677,7 @@ lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
static void
statext_store(Oid statOid,
MVNDistinct *ndistinct, MVDependencies *dependencies,
- MCVList *mcv, VacAttrStats **stats)
+ MCVList *mcv, Datum exprs, VacAttrStats **stats)
{
Relation pg_stextdata;
HeapTuple stup,
@@ -532,11 +718,17 @@ statext_store(Oid statOid,
nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = (data == NULL);
values[Anum_pg_statistic_ext_data_stxdmcv - 1] = PointerGetDatum(data);
}
+ if (exprs != (Datum) 0)
+ {
+ nulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = false;
+ values[Anum_pg_statistic_ext_data_stxdexpr - 1] = exprs;
+ }
/* always replace the value (either by bytea or NULL) */
replaces[Anum_pg_statistic_ext_data_stxdndistinct - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxddependencies - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
+ replaces[Anum_pg_statistic_ext_data_stxdexpr - 1] = true;
/* there should already be a pg_statistic_ext_data tuple */
oldtup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(statOid));
@@ -741,8 +933,9 @@ build_attnums_array(Bitmapset *attrs, int *numattrs)
* can simply pfree the return value to release all of it.
*/
SortItem *
-build_sorted_items(int numrows, int *nitems, HeapTuple *rows, TupleDesc tdesc,
- MultiSortSupport mss, int numattrs, AttrNumber *attnums)
+build_sorted_items(int numrows, int *nitems, HeapTuple *rows, ExprInfo *exprs,
+ TupleDesc tdesc, MultiSortSupport mss,
+ int numattrs, AttrNumber *attnums)
{
int i,
j,
@@ -789,8 +982,24 @@ build_sorted_items(int numrows, int *nitems, HeapTuple *rows, TupleDesc tdesc,
{
Datum value;
bool isnull;
+ int attlen;
- value = heap_getattr(rows[i], attnums[j], tdesc, &isnull);
+ if (attnums[j] <= MaxHeapAttributeNumber)
+ {
+ value = heap_getattr(rows[i], attnums[j], tdesc, &isnull);
+ attlen = TupleDescAttr(tdesc, attnums[j] - 1)->attlen;
+ }
+ else
+ {
+ int idx = EXPRESSION_INDEX(attnums[j]);
+
+ Assert((idx >= 0) && (idx < exprs->nexprs));
+
+ value = exprs->values[idx][i];
+ isnull = exprs->nulls[idx][i];
+
+ attlen = get_typlen(exprs->types[idx]);
+ }
/*
* If this is a varlena value, check if it's too wide and if yes
@@ -801,8 +1010,7 @@ build_sorted_items(int numrows, int *nitems, HeapTuple *rows, TupleDesc tdesc,
* on the assumption that those are small (below WIDTH_THRESHOLD)
* and will be discarded at the end of analyze.
*/
- if ((!isnull) &&
- (TupleDescAttr(tdesc, attnums[j] - 1)->attlen == -1))
+ if ((!isnull) && (attlen == -1))
{
if (toast_raw_datum_size(value) > WIDTH_THRESHOLD)
{
@@ -881,7 +1089,8 @@ has_stats_of_kind(List *stats, char requiredkind)
*/
StatisticExtInfo *
choose_best_statistics(List *stats, char requiredkind,
- Bitmapset **clause_attnums, int nclauses)
+ Bitmapset **clause_attnums, List **clause_exprs,
+ int nclauses)
{
ListCell *lc;
StatisticExtInfo *best_match = NULL;
@@ -894,6 +1103,7 @@ choose_best_statistics(List *stats, char requiredkind,
StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
Bitmapset *matched = NULL;
int num_matched;
+ int num_matched_exprs;
int numkeys;
/* skip statistics that are not of the correct type */
@@ -920,6 +1130,38 @@ choose_best_statistics(List *stats, char requiredkind,
num_matched = bms_num_members(matched);
bms_free(matched);
+ /*
+ * Collect expressions in remaining (unestimated) expressions, covered
+ * by an expression in this statistic object.
+ */
+ num_matched_exprs = 0;
+ for (i = 0; i < nclauses; i++)
+ {
+ ListCell *lc3;
+
+ /* ignore incompatible/estimated expressions */
+ if (!clause_exprs[i])
+ continue;
+
+ /* ignore expressions that are not covered by this object */
+ foreach (lc3, clause_exprs[i])
+ {
+ ListCell *lc2;
+ Node *expr = (Node *) lfirst(lc3);
+
+ foreach(lc2, info->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(expr, stat_expr))
+ {
+ num_matched_exprs++;
+ break;
+ }
+ }
+ }
+ }
+
/*
* save the actual number of keys in the stats so that we can choose
* the narrowest stats with the most matching keys.
@@ -931,11 +1173,12 @@ choose_best_statistics(List *stats, char requiredkind,
* when it matches the same number of attributes but these stats have
* fewer keys than any previous match.
*/
- if (num_matched > best_num_matched ||
- (num_matched == best_num_matched && numkeys < best_match_keys))
+ if (num_matched + num_matched_exprs > best_num_matched ||
+ ((num_matched + num_matched_exprs) == best_num_matched &&
+ numkeys < best_match_keys))
{
best_match = info;
- best_num_matched = num_matched;
+ best_num_matched = num_matched + num_matched_exprs;
best_match_keys = numkeys;
}
}
@@ -994,7 +1237,7 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
return false;
/* Check if the expression has the right shape (one Var, one Const) */
- if (!examine_clause_args(expr->args, &var, NULL, NULL))
+ if (!examine_opclause_expression(expr, &var, NULL, NULL))
return false;
/*
@@ -1150,6 +1393,214 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
return false;
}
+/*
+ * statext_extract_expression_internal
+ * Extract parts of an expressions to match against extended stats.
+ *
+ * Given an expression, decompose it into "parts" that will be analyzed and
+ * matched against extended statistics. If the expression is not considered
+ * compatible (supported by extended statistics), this returns NIL.
+ *
+ * There's a certain amount of ambiguity, because some expressions may be
+ * split into parts in multiple ways. For example, consider expression
+ *
+ * (a + b) = 1
+ *
+ * which may be either considered as a single boolean expression, or it may
+ * be split into expression (a + b) and a constant. So this might return
+ * either ((a+b)=1) or (a+b) as valid expressions, but this does affect
+ * matching to extended statistics, because the expressions have to match
+ * the definition exactly. So ((a+b)=1) would match statistics defined as
+ *
+ * CREATE STATISTICS s ON ((a+b) = 1) FROM t;
+ *
+ * but not
+ *
+ * CREATE STATISTICS s ON (a+b) FROM t;
+ *
+ * which might be a bit confusing. We might enhance this to track those
+ * alternative decompositions somehow, and then modify the matching to
+ * extended statistics. But it seems non-trivial, because the AND/OR
+ * clauses make it "recursive".
+ *
+ * in which expressions might be extracted.
+ */
+static List *
+statext_extract_expression_internal(PlannerInfo *root, Node *clause, Index relid)
+{
+ /* Look inside any binary-compatible relabeling (as in examine_variable) */
+ if (IsA(clause, RelabelType))
+ clause = (Node *) ((RelabelType *) clause)->arg;
+
+ /* plain Var references (boolean Vars or recursive checks) */
+ if (IsA(clause, Var))
+ {
+ Var *var = (Var *) clause;
+
+ /* Ensure var is from the correct relation */
+ if (var->varno != relid)
+ return NIL;
+
+ /* we also better ensure the Var is from the current level */
+ if (var->varlevelsup > 0)
+ return NIL;
+
+ /* Also skip system attributes (we don't allow stats on those). */
+ if (!AttrNumberIsForUserDefinedAttr(var->varattno))
+ return NIL;
+
+ return list_make1(clause);
+ }
+
+ /* (Var op Const) or (Const op Var) */
+ if (is_opclause(clause))
+ {
+ RangeTblEntry *rte = root->simple_rte_array[relid];
+ OpExpr *expr = (OpExpr *) clause;
+ Node *expr2 = NULL;
+
+ /* Only expressions with two arguments are considered compatible. */
+ if (list_length(expr->args) != 2)
+ return NIL;
+
+ /* Check if the expression has the right shape (one Expr, one Const) */
+ if (!examine_opclause_expression2(expr, &expr2, NULL, NULL))
+ return NIL;
+
+ /*
+ * If it's not one of the supported operators ("=", "<", ">", etc.),
+ * just ignore the clause, as it's not compatible with MCV lists.
+ *
+ * This uses the function for estimating selectivity, not the operator
+ * directly (a bit awkward, but well ...).
+ */
+ switch (get_oprrest(expr->opno))
+ {
+ case F_EQSEL:
+ case F_NEQSEL:
+ case F_SCALARLTSEL:
+ case F_SCALARLESEL:
+ case F_SCALARGTSEL:
+ case F_SCALARGESEL:
+ /* supported, will continue with inspection of the Var */
+ break;
+
+ default:
+ /* other estimators are considered unknown/unsupported */
+ return NIL;
+ }
+
+ /*
+ * If there are any securityQuals on the RTE from security barrier
+ * views or RLS policies, then the user may not have access to all the
+ * table's data, and we must check that the operator is leak-proof.
+ *
+ * If the operator is leaky, then we must ignore this clause for the
+ * purposes of estimating with MCV lists, otherwise the operator might
+ * reveal values from the MCV list that the user doesn't have
+ * permission to see.
+ */
+ if (rte->securityQuals != NIL &&
+ !get_func_leakproof(get_opcode(expr->opno)))
+ return NIL;
+
+ return list_make1(expr2);
+ }
+
+ if (IsA(clause, ScalarArrayOpExpr))
+ {
+ RangeTblEntry *rte = root->simple_rte_array[relid];
+ ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) clause;
+ Node *expr2 = NULL;
+
+ /* Only expressions with two arguments are considered compatible. */
+ if (list_length(expr->args) != 2)
+ return NIL;
+
+ /* Check if the expression has the right shape (one Expr, one Const) */
+ if (!examine_clause_args2(expr->args, &expr2, NULL, NULL))
+ return NIL;
+
+ /*
+ * If there are any securityQuals on the RTE from security barrier
+ * views or RLS policies, then the user may not have access to all the
+ * table's data, and we must check that the operator is leak-proof.
+ *
+ * If the operator is leaky, then we must ignore this clause for the
+ * purposes of estimating with MCV lists, otherwise the operator might
+ * reveal values from the MCV list that the user doesn't have
+ * permission to see.
+ */
+ if (rte->securityQuals != NIL &&
+ !get_func_leakproof(get_opcode(expr->opno)))
+ return NIL;
+
+ return list_make1(expr2);
+ }
+
+ /* AND/OR/NOT clause */
+ if (is_andclause(clause) ||
+ is_orclause(clause) ||
+ is_notclause(clause))
+ {
+ /*
+ * AND/OR/NOT-clauses are supported if all sub-clauses are supported
+ *
+ * Perhaps we could improve this by handling mixed cases, when some of
+ * the clauses are supported and some are not. Selectivity for the
+ * supported subclauses would be computed using extended statistics,
+ * and the remaining clauses would be estimated using the traditional
+ * algorithm (product of selectivities).
+ *
+ * It however seems overly complex, and in a way we already do that
+ * because if we reject the whole clause as unsupported here, it will
+ * be eventually passed to clauselist_selectivity() which does exactly
+ * this (split into supported/unsupported clauses etc).
+ */
+ BoolExpr *expr = (BoolExpr *) clause;
+ ListCell *lc;
+ List *exprs = NIL;
+
+ foreach(lc, expr->args)
+ {
+ List *tmp;
+
+ /*
+ * Had we found incompatible clause in the arguments, treat the
+ * whole clause as incompatible.
+ */
+ tmp = statext_extract_expression_internal(root,
+ (Node *) lfirst(lc),
+ relid);
+
+ if (!tmp)
+ return NIL;
+
+ exprs = list_concat(exprs, tmp);
+ }
+
+ return exprs;
+ }
+
+ /* Var IS NULL */
+ if (IsA(clause, NullTest))
+ {
+ NullTest *nt = (NullTest *) clause;
+
+ /*
+ * Only simple (Var IS NULL) expressions supported for now. Maybe we
+ * could use examine_variable to fix this?
+ */
+ if (!IsA(nt->arg, Var))
+ return NIL;
+
+ return statext_extract_expression_internal(root, (Node *) (nt->arg),
+ relid);
+ }
+
+ return NIL;
+}
+
/*
* statext_is_compatible_clause
* Determines if the clause is compatible with MCV lists.
@@ -1163,6 +1614,8 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
*
* (c) combinations using AND/OR/NOT
*
+ * (d) ScalarArrayOpExprs of the form (Var op ANY (array)) or (Var op ALL (array))
+ *
* In the future, the range of supported clauses may be expanded to more
* complex cases, for example (Var op Var).
*/
@@ -1250,13 +1703,108 @@ statext_is_compatible_clause(PlannerInfo *root, Node *clause, Index relid,
}
/*
- * statext_mcv_clauselist_selectivity
- * Estimate clauses using the best multi-column statistics.
+ * statext_extract_expression
+ * Determines if the clause is compatible with extended statistics.
*
- * Applies available extended (multi-column) statistics on a table. There may
- * be multiple applicable statistics (with respect to the clauses), in which
- * case we use greedy approach. In each round we select the best statistic on
- * a table (measured by the number of attributes extracted from the clauses
+ * Currently, we only support three types of clauses:
+ *
+ * (a) OpExprs of the form (Var op Const), or (Const op Var), where the op
+ * is one of ("=", "<", ">", ">=", "<=")
+ *
+ * (b) (Var IS [NOT] NULL)
+ *
+ * (c) combinations using AND/OR/NOT
+ *
+ * (d) ScalarArrayOpExprs of the form (Var op ANY (array)) or (Var op ALL (array))
+ *
+ * In the future, the range of supported clauses may be expanded to more
+ * complex cases, for example (Var op Var).
+ */
+static List *
+statext_extract_expression(PlannerInfo *root, Node *clause, Index relid)
+{
+ RestrictInfo *rinfo = (RestrictInfo *) clause;
+ RangeTblEntry *rte = root->simple_rte_array[relid];
+ List *exprs;
+ Oid userid;
+
+ if (!IsA(rinfo, RestrictInfo))
+ return NIL;
+
+ /* Pseudoconstants are not really interesting here. */
+ if (rinfo->pseudoconstant)
+ return NIL;
+
+ /* clauses referencing multiple varnos are incompatible */
+ if (bms_membership(rinfo->clause_relids) != BMS_SINGLETON)
+ return NIL;
+
+ /* Check the clause and extract expressions it's composed of. */
+ exprs = statext_extract_expression_internal(root, (Node *) rinfo->clause, relid);
+
+ /*
+ * If there are no potentially interesting expressions (supported by
+ * extended statistics), we're done;
+ */
+ if (!exprs)
+ return NIL;
+
+ /*
+ * Check that the user has permission to read all these attributes. Use
+ * checkAsUser if it's set, in case we're accessing the table via a view.
+ */
+ userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
+
+ if (pg_class_aclcheck(rte->relid, userid, ACL_SELECT) != ACLCHECK_OK)
+ {
+ Bitmapset *attnums = NULL;
+
+ /* Extract all attribute numbers from the expressions. */
+ pull_varattnos((Node *) exprs, relid, &attnums);
+
+ /* Don't have table privilege, must check individual columns */
+ if (bms_is_member(InvalidAttrNumber, attnums))
+ {
+ /* Have a whole-row reference, must have access to all columns */
+ if (pg_attribute_aclcheck_all(rte->relid, userid, ACL_SELECT,
+ ACLMASK_ALL) != ACLCHECK_OK)
+ return NIL;
+ }
+ else
+ {
+ /* Check the columns referenced by the clause */
+ int attnum = -1;
+
+ while ((attnum = bms_next_member(attnums, attnum)) >= 0)
+ {
+ AttrNumber tmp;
+
+ /* Adjust for system attributes (offset for bitmap). */
+ tmp = attnum + FirstLowInvalidHeapAttributeNumber;
+
+ /* Ignore system attributes, those can't have statistics. */
+ if (!AttrNumberIsForUserDefinedAttr(tmp))
+ return NIL;
+
+ if (pg_attribute_aclcheck(rte->relid, tmp, userid,
+ ACL_SELECT) != ACLCHECK_OK)
+ return NIL;
+ }
+ }
+ }
+
+ /* If we reach here, the clause is OK */
+ return exprs;
+}
+
+/*
+ * statext_mcv_clauselist_selectivity
+ * Estimate clauses using the best multi-column statistics.
+ *
+ * Applies available extended (multi-column) statistics on a table. There may
+ * be multiple applicable statistics (with respect to the clauses), in which
+ * case we use greedy approach. In each round we select the best statistic on
+ * a table (measured by the number of attributes extracted from the clauses
* and covered by it), and compute the selectivity for the supplied clauses.
* We repeat this process with the remaining clauses (if any), until none of
* the available statistics can be used.
@@ -1290,7 +1838,8 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
bool is_or)
{
ListCell *l;
- Bitmapset **list_attnums;
+ Bitmapset **list_attnums; /* attnums extracted from the clause */
+ List **list_exprs; /* expressions matched to any statistic */
int listidx;
Selectivity sel = (is_or) ? 0.0 : 1.0;
@@ -1301,6 +1850,9 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
list_attnums = (Bitmapset **) palloc(sizeof(Bitmapset *) *
list_length(clauses));
+ /* expressions extracted from complex expressions */
+ list_exprs = (List **) palloc(sizeof(Node *) * list_length(clauses));
+
/*
* Pre-process the clauses list to extract the attnums seen in each item.
* We need to determine if there's any clauses which will be useful for
@@ -1318,11 +1870,100 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
Node *clause = (Node *) lfirst(l);
Bitmapset *attnums = NULL;
+ /* the clause is considered incompatible by default */
+ list_attnums[listidx] = NULL;
+
+ /* and it's also not covered exactly by the statistic */
+ list_exprs[listidx] = NULL;
+
+ /*
+ * First see if the clause is simple enough to be covered directly
+ * by the attributes. If not, see if there's at least one statistic
+ * object using the expression as-is.
+ */
if (!bms_is_member(listidx, *estimatedclauses) &&
statext_is_compatible_clause(root, clause, rel->relid, &attnums))
+ {
+ /* simple expression, covered through attnum(s) */
list_attnums[listidx] = attnums;
+ }
else
- list_attnums[listidx] = NULL;
+ {
+ ListCell *lc;
+ List *exprs;
+
+ /*
+ * XXX This is kinda dubious, because we extract the smallest
+ * clauses - e.g. from (Var op Const) we extract Var. But maybe
+ * the statistics covers larger expressions, so maybe this will
+ * skip that. For example give ((a+b) + (c+d)) it's not clear
+ * if we should extract the whole clause or some smaller parts.
+ * OTOH we need (Expr op Const) so maybe we only care about the
+ * clause as a whole?
+ */
+ exprs = statext_extract_expression(root, clause, rel->relid);
+
+ /* complex expression, search for statistic covering all parts */
+ foreach(lc, rel->statlist)
+ {
+ ListCell *le;
+ StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
+
+ /*
+ * Assume all parts are covered by this statistics, we'll
+ * stop if we found part that is not covered.
+ */
+ bool covered = true;
+
+ /* have we already matched the expression to a statistic? */
+ Assert(!list_exprs[listidx]);
+
+ /* no expressions in the statistic */
+ if (!info->exprs)
+ continue;
+
+ foreach(le, exprs)
+ {
+ ListCell *lc2;
+ Node *expr = (Node *) lfirst(le);
+ bool found = false;
+
+ /*
+ * Walk the expressions, see if all expressions extracted from
+ * the clause are covered by the extended statistic object.
+ */
+ foreach (lc2, info->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(expr, stat_expr))
+ {
+ found = true;
+ break;
+ }
+ }
+
+ /* found expression not covered by the statistics, stop */
+ if (!found)
+ {
+ covered = false;
+ break;
+ }
+ }
+
+ /*
+ * OK, we found a statistics covering this clause, stop looking
+ * for another one
+ */
+ if (covered)
+ {
+ /* XXX should this add the original expression instead? */
+ list_exprs[listidx] = exprs;
+ break;
+ }
+
+ }
+ }
listidx++;
}
@@ -1336,7 +1977,8 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
/* find the best suited statistics object for these attnums */
stat = choose_best_statistics(rel->statlist, STATS_EXT_MCV,
- list_attnums, list_length(clauses));
+ list_attnums, list_exprs,
+ list_length(clauses));
/*
* if no (additional) matching stats could be found then we've nothing
@@ -1359,11 +2001,13 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
{
/*
* If the clause is compatible with the selected statistics, mark
- * it as estimated and add it to the list to estimate.
+ * it as estimated and add it to the list to estimate. It may be
+ * either a simple clause, or an expression.
*/
if (list_attnums[listidx] != NULL &&
bms_is_subset(list_attnums[listidx], stat->keys))
{
+ /* simple clause (single Var) */
if (bms_membership(list_attnums[listidx]) == BMS_SINGLETON)
simple_clauses = bms_add_member(simple_clauses,
list_length(stat_clauses));
@@ -1374,6 +2018,45 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
bms_free(list_attnums[listidx]);
list_attnums[listidx] = NULL;
}
+ else if (list_exprs[listidx] != NIL)
+ {
+ /* are all parts of the expression covered by the statistic? */
+ ListCell *lc;
+ int ncovered = 0;
+
+ foreach (lc, list_exprs[listidx])
+ {
+ ListCell *lc2;
+ Node *expr = (Node *) lfirst(lc);
+ bool found = false;
+
+ foreach (lc2, stat->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(expr, stat_expr))
+ {
+ found = true;
+ break;
+ }
+ }
+
+ /* count it as covered and continue to the next expression */
+ if (found)
+ ncovered++;
+ }
+
+ /* all parts of the expression are covered by this statistics */
+ if (ncovered == list_length(list_exprs[listidx]))
+ {
+ stat_clauses = lappend(stat_clauses, (Node *) lfirst(l));
+ *estimatedclauses = bms_add_member(*estimatedclauses, listidx);
+
+ list_free(list_exprs[listidx]);
+ list_exprs[listidx] = NULL;
+ }
+
+ }
listidx++;
}
@@ -1621,3 +2304,788 @@ examine_clause_args(List *args, Var **varp, Const **cstp, bool *varonleftp)
return true;
}
+
+bool
+examine_clause_args2(List *args, Node **exprp, Const **cstp, bool *expronleftp)
+{
+ Node *expr;
+ Const *cst;
+ bool expronleft;
+ Node *leftop,
+ *rightop;
+
+ /* enforced by statext_is_compatible_clause_internal */
+ Assert(list_length(args) == 2);
+
+ leftop = linitial(args);
+ rightop = lsecond(args);
+
+ /* strip RelabelType from either side of the expression */
+ if (IsA(leftop, RelabelType))
+ leftop = (Node *) ((RelabelType *) leftop)->arg;
+
+ if (IsA(rightop, RelabelType))
+ rightop = (Node *) ((RelabelType *) rightop)->arg;
+
+ if (IsA(rightop, Const))
+ {
+ expr = (Node *) leftop;
+ cst = (Const *) rightop;
+ expronleft = true;
+ }
+ else if (IsA(leftop, Const))
+ {
+ expr = (Node *) rightop;
+ cst = (Const *) leftop;
+ expronleft = false;
+ }
+ else
+ return false;
+
+ /* return pointers to the extracted parts if requested */
+ if (exprp)
+ *exprp = expr;
+
+ if (cstp)
+ *cstp = cst;
+
+ if (expronleftp)
+ *expronleftp = expronleft;
+
+ return true;
+}
+
+bool
+examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonleftp)
+{
+ Var *var;
+ Const *cst;
+ bool varonleft;
+ Node *leftop,
+ *rightop;
+
+ /* enforced by statext_is_compatible_clause_internal */
+ Assert(list_length(expr->args) == 2);
+
+ leftop = linitial(expr->args);
+ rightop = lsecond(expr->args);
+
+ /* strip RelabelType from either side of the expression */
+ if (IsA(leftop, RelabelType))
+ leftop = (Node *) ((RelabelType *) leftop)->arg;
+
+ if (IsA(rightop, RelabelType))
+ rightop = (Node *) ((RelabelType *) rightop)->arg;
+
+ if (IsA(leftop, Var) && IsA(rightop, Const))
+ {
+ var = (Var *) leftop;
+ cst = (Const *) rightop;
+ varonleft = true;
+ }
+ else if (IsA(leftop, Const) && IsA(rightop, Var))
+ {
+ var = (Var *) rightop;
+ cst = (Const *) leftop;
+ varonleft = false;
+ }
+ else
+ return false;
+
+ /* return pointers to the extracted parts if requested */
+ if (varp)
+ *varp = var;
+
+ if (cstp)
+ *cstp = cst;
+
+ if (varonleftp)
+ *varonleftp = varonleft;
+
+ return true;
+}
+
+bool
+examine_opclause_expression2(OpExpr *expr, Node **exprp, Const **cstp, bool *expronleftp)
+{
+ Node *expr2;
+ Const *cst;
+ bool expronleft;
+ Node *leftop,
+ *rightop;
+
+ /* enforced by statext_is_compatible_clause_internal */
+ Assert(list_length(expr->args) == 2);
+
+ leftop = linitial(expr->args);
+ rightop = lsecond(expr->args);
+
+ /* strip RelabelType from either side of the expression */
+ if (IsA(leftop, RelabelType))
+ leftop = (Node *) ((RelabelType *) leftop)->arg;
+
+ if (IsA(rightop, RelabelType))
+ rightop = (Node *) ((RelabelType *) rightop)->arg;
+
+ if (IsA(rightop, Const))
+ {
+ expr2 = (Node *) leftop;
+ cst = (Const *) rightop;
+ expronleft = true;
+ }
+ else if (IsA(leftop, Const))
+ {
+ expr2 = (Node *) rightop;
+ cst = (Const *) leftop;
+ expronleft = false;
+ }
+ else
+ return false;
+
+ /* return pointers to the extracted parts if requested */
+ if (exprp)
+ *exprp = expr2;
+
+ if (cstp)
+ *cstp = cst;
+
+ if (expronleftp)
+ *expronleftp = expronleft;
+
+ return true;
+}
+
+
+/*
+ * Compute statistics about expressions of a relation.
+ */
+static void
+compute_expr_stats(Relation onerel, double totalrows,
+ AnlExprData *exprdata, int nexprs,
+ HeapTuple *rows, int numrows)
+{
+ MemoryContext expr_context,
+ old_context;
+ int ind,
+ i;
+
+ expr_context = AllocSetContextCreate(CurrentMemoryContext,
+ "Analyze Expression",
+ ALLOCSET_DEFAULT_SIZES);
+ old_context = MemoryContextSwitchTo(expr_context);
+
+ for (ind = 0; ind < nexprs; ind++)
+ {
+ AnlExprData *thisdata = &exprdata[ind];
+ VacAttrStats *stats = thisdata->vacattrstat;
+ Node *expr = thisdata->expr;
+ TupleTableSlot *slot;
+ EState *estate;
+ ExprContext *econtext;
+ Datum *exprvals;
+ bool *exprnulls;
+ ExprState *exprstate;
+ int tcnt;
+
+ /* Are we still in the main context? */
+ Assert(CurrentMemoryContext == expr_context);
+
+ /*
+ * Need an EState for evaluation of expressions. Create it in
+ * the per-expression context to be sure it gets cleaned up at
+ * the bottom of the loop.
+ */
+ estate = CreateExecutorState();
+ econtext = GetPerTupleExprContext(estate);
+
+ /* Set up expression evaluation state */
+ exprstate = ExecPrepareExpr((Expr *) expr, estate);
+
+ /* Need a slot to hold the current heap tuple, too */
+ slot = MakeSingleTupleTableSlot(RelationGetDescr(onerel),
+ &TTSOpsHeapTuple);
+
+ /* Arrange for econtext's scan tuple to be the tuple under test */
+ econtext->ecxt_scantuple = slot;
+
+ /* Compute and save index expression values */
+ exprvals = (Datum *) palloc(numrows * sizeof(Datum));
+ exprnulls = (bool *) palloc(numrows * sizeof(bool));
+
+ tcnt = 0;
+ for (i = 0; i < numrows; i++)
+ {
+ Datum datum;
+ bool isnull;
+
+ /*
+ * Reset the per-tuple context each time, to reclaim any cruft
+ * left behind by evaluating the predicate or index expressions.
+ */
+ ResetExprContext(econtext);
+
+ /* Set up for expression evaluation */
+ ExecStoreHeapTuple(rows[i], slot, false);
+
+ /*
+ * Evaluate the expression. We do this in the per-tuple context
+ * so as not to leak memory, and then copy the result into the
+ * context created at the beginning of this function.
+ */
+ datum = ExecEvalExprSwitchContext(exprstate,
+ GetPerTupleExprContext(estate),
+ &isnull);
+ if (isnull)
+ {
+ exprvals[tcnt] = (Datum) 0;
+ exprnulls[tcnt] = true;
+ }
+ else
+ {
+ /* Make sure we copy the data into the context. */
+ Assert(CurrentMemoryContext == expr_context);
+
+ exprvals[tcnt] = datumCopy(datum,
+ stats->attrtype->typbyval,
+ stats->attrtype->typlen);
+ exprnulls[tcnt] = false;
+ }
+
+ tcnt++;
+ }
+
+ /*
+ * Now we can compute the statistics for the expression columns.
+ *
+ * XXX Unlike compute_index_stats we don't need to switch and reset
+ * memory contexts here, because we're only computing stats for a
+ * single expression (and not iterating over many indexes), so we
+ * just do it in expr_context. Note that compute_stats copies the
+ * result into stats->anl_context, so it does not disappear.
+ */
+ if (tcnt > 0)
+ {
+ AttributeOpts *aopt =
+ get_attribute_options(stats->attr->attrelid,
+ stats->attr->attnum);
+
+ stats->exprvals = exprvals;
+ stats->exprnulls = exprnulls;
+ stats->rowstride = 1;
+ stats->compute_stats(stats,
+ expr_fetch_func,
+ tcnt,
+ tcnt);
+
+ /*
+ * If the n_distinct option is specified, it overrides the
+ * above computation.
+ */
+ if (aopt != NULL && aopt->n_distinct != 0.0)
+ stats->stadistinct = aopt->n_distinct;
+ }
+
+ /* And clean up */
+ MemoryContextSwitchTo(expr_context);
+
+ ExecDropSingleTupleTableSlot(slot);
+ FreeExecutorState(estate);
+ MemoryContextResetAndDeleteChildren(expr_context);
+ }
+
+ MemoryContextSwitchTo(old_context);
+ MemoryContextDelete(expr_context);
+}
+
+
+/*
+ * Fetch function for analyzing index expressions.
+ *
+ * We have not bothered to construct index tuples, instead the data is
+ * just in Datum arrays.
+ */
+static Datum
+expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull)
+{
+ int i;
+
+ /* exprvals and exprnulls are already offset for proper column */
+ i = rownum * stats->rowstride;
+ *isNull = stats->exprnulls[i];
+ return stats->exprvals[i];
+}
+
+/*
+ * Build analyze data for a list of expressions. As this is not tied
+ * directly to a relation (table or index), we have to fake some of
+ * the data.
+ */
+static AnlExprData *
+build_expr_data(List *exprs)
+{
+ int idx;
+ int nexprs = list_length(exprs);
+ AnlExprData *exprdata;
+ ListCell *lc;
+
+ exprdata = (AnlExprData *) palloc0(nexprs * sizeof(AnlExprData));
+
+ idx = 0;
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+ AnlExprData *thisdata = &exprdata[idx];
+
+ thisdata->expr = expr;
+ thisdata->vacattrstat = (VacAttrStats *) palloc(sizeof(VacAttrStats));
+
+ thisdata->vacattrstat = examine_expression(expr);
+ idx++;
+ }
+
+ return exprdata;
+}
+
+/*
+ * examine_expression -- pre-analysis of a single column
+ *
+ * Determine whether the column is analyzable; if so, create and initialize
+ * a VacAttrStats struct for it. If not, return NULL.
+ */
+static VacAttrStats *
+examine_expression(Node *expr)
+{
+ HeapTuple typtuple;
+ VacAttrStats *stats;
+ int i;
+ bool ok;
+
+ Assert(expr != NULL);
+
+ /*
+ * Create the VacAttrStats struct.
+ */
+ stats = (VacAttrStats *) palloc0(sizeof(VacAttrStats));
+
+ /*
+ * When analyzing an expression, believe the expression tree's type.
+ */
+ stats->attrtypid = exprType(expr);
+ stats->attrtypmod = exprTypmod(expr);
+
+ /*
+ * XXX Do we need to do anything special about the collation, similar
+ * to what examine_attribute does for expression indexes?
+ */
+ stats->attrcollid = exprCollation(expr);
+
+ /*
+ * We don't have any pg_attribute for expressions, so let's fake
+ * something reasonable into attstattarget, which is the only thing
+ * std_typanalyze needs.
+ */
+ stats->attr = (Form_pg_attribute) palloc(ATTRIBUTE_FIXED_PART_SIZE);
+
+ /*
+ * FIXME we should probably get the target from the extended stats
+ * object, or something like that.
+ */
+ stats->attr->attstattarget = default_statistics_target;
+
+ /* initialize some basic fields */
+ stats->attr->attrelid = InvalidOid;
+ stats->attr->attnum = InvalidAttrNumber;
+ stats->attr->atttypid = stats->attrtypid;
+
+ typtuple = SearchSysCacheCopy1(TYPEOID,
+ ObjectIdGetDatum(stats->attrtypid));
+ if (!HeapTupleIsValid(typtuple))
+ elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
+ stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
+ stats->anl_context = CurrentMemoryContext; /* XXX should be using something else? */
+ stats->tupattnum = InvalidAttrNumber;
+
+ /*
+ * The fields describing the stats->stavalues[n] element types default to
+ * the type of the data being analyzed, but the type-specific typanalyze
+ * function can change them if it wants to store something else.
+ */
+ for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
+ {
+ stats->statypid[i] = stats->attrtypid;
+ stats->statyplen[i] = stats->attrtype->typlen;
+ stats->statypbyval[i] = stats->attrtype->typbyval;
+ stats->statypalign[i] = stats->attrtype->typalign;
+ }
+
+ /*
+ * Call the type-specific typanalyze function. If none is specified, use
+ * std_typanalyze().
+ */
+ if (OidIsValid(stats->attrtype->typanalyze))
+ ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
+ PointerGetDatum(stats)));
+ else
+ ok = std_typanalyze(stats);
+
+ if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
+ {
+ heap_freetuple(typtuple);
+ pfree(stats);
+ return NULL;
+ }
+
+ return stats;
+}
+
+/* form an array of pg_statistic rows (per update_attstats) */
+static Datum
+serialize_expr_stats(AnlExprData *exprdata, int nexprs)
+{
+ int exprno;
+ Oid typOid;
+ Relation sd;
+
+ ArrayBuildState *astate = NULL;
+
+ sd = table_open(StatisticRelationId, RowExclusiveLock);
+
+ /* lookup OID of composite type for pg_statistic */
+ typOid = get_rel_type_id(StatisticRelationId);
+ if (!OidIsValid(typOid))
+ ereport(ERROR,
+ (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+ errmsg("relation \"pg_statistic\" does not have a composite type")));
+
+ for (exprno = 0; exprno < nexprs; exprno++)
+ {
+ int i, k;
+ VacAttrStats *stats = exprdata[exprno].vacattrstat;
+
+ Datum values[Natts_pg_statistic];
+ bool nulls[Natts_pg_statistic];
+ HeapTuple stup;
+
+ if (!stats->stats_valid)
+ {
+ astate = accumArrayResult(astate,
+ (Datum) 0,
+ true,
+ typOid,
+ CurrentMemoryContext);
+ continue;
+ }
+
+ /*
+ * Construct a new pg_statistic tuple
+ */
+ for (i = 0; i < Natts_pg_statistic; ++i)
+ {
+ nulls[i] = false;
+ }
+
+ values[Anum_pg_statistic_starelid - 1] = ObjectIdGetDatum(InvalidOid);
+ values[Anum_pg_statistic_staattnum - 1] = Int16GetDatum(InvalidAttrNumber);
+ values[Anum_pg_statistic_stainherit - 1] = BoolGetDatum(false);
+ values[Anum_pg_statistic_stanullfrac - 1] = Float4GetDatum(stats->stanullfrac);
+ values[Anum_pg_statistic_stawidth - 1] = Int32GetDatum(stats->stawidth);
+ values[Anum_pg_statistic_stadistinct - 1] = Float4GetDatum(stats->stadistinct);
+ i = Anum_pg_statistic_stakind1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ values[i++] = Int16GetDatum(stats->stakind[k]); /* stakindN */
+ }
+ i = Anum_pg_statistic_staop1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ values[i++] = ObjectIdGetDatum(stats->staop[k]); /* staopN */
+ }
+ i = Anum_pg_statistic_stacoll1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ values[i++] = ObjectIdGetDatum(stats->stacoll[k]); /* stacollN */
+ }
+ i = Anum_pg_statistic_stanumbers1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ int nnum = stats->numnumbers[k];
+
+ if (nnum > 0)
+ {
+ int n;
+ Datum *numdatums = (Datum *) palloc(nnum * sizeof(Datum));
+ ArrayType *arry;
+
+ for (n = 0; n < nnum; n++)
+ numdatums[n] = Float4GetDatum(stats->stanumbers[k][n]);
+ /* XXX knows more than it should about type float4: */
+ arry = construct_array(numdatums, nnum,
+ FLOAT4OID,
+ sizeof(float4), true, TYPALIGN_INT);
+ values[i++] = PointerGetDatum(arry); /* stanumbersN */
+ }
+ else
+ {
+ nulls[i] = true;
+ values[i++] = (Datum) 0;
+ }
+ }
+ i = Anum_pg_statistic_stavalues1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ if (stats->numvalues[k] > 0)
+ {
+ ArrayType *arry;
+
+ arry = construct_array(stats->stavalues[k],
+ stats->numvalues[k],
+ stats->statypid[k],
+ stats->statyplen[k],
+ stats->statypbyval[k],
+ stats->statypalign[k]);
+ values[i++] = PointerGetDatum(arry); /* stavaluesN */
+ }
+ else
+ {
+ nulls[i] = true;
+ values[i++] = (Datum) 0;
+ }
+ }
+
+ stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+
+ astate = accumArrayResult(astate,
+ heap_copy_tuple_as_datum(stup, RelationGetDescr(sd)),
+ false,
+ typOid,
+ CurrentMemoryContext);
+ }
+
+ table_close(sd, RowExclusiveLock);
+
+ return makeArrayResult(astate, CurrentMemoryContext);
+}
+
+
+/*
+ * Loads pg_statistic record from expression statistics for expression
+ * identified by the supplied index.
+ */
+HeapTuple
+statext_expressions_load(Oid stxoid, int idx)
+{
+ bool isnull;
+ Datum value;
+ HeapTuple htup;
+ ExpandedArrayHeader *eah;
+ HeapTupleHeader td;
+ HeapTupleData tmptup;
+ HeapTuple tup;
+
+ htup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(stxoid));
+ if (!HeapTupleIsValid(htup))
+ elog(ERROR, "cache lookup failed for statistics object %u", stxoid);
+
+ value = SysCacheGetAttr(STATEXTDATASTXOID, htup,
+ Anum_pg_statistic_ext_data_stxdexpr, &isnull);
+ if (isnull)
+ elog(ERROR,
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
+ STATS_EXT_DEPENDENCIES, stxoid);
+
+ eah = DatumGetExpandedArray(value);
+
+ deconstruct_expanded_array(eah);
+
+ td = DatumGetHeapTupleHeader(eah->dvalues[idx]);
+
+ /* Build a temporary HeapTuple control structure */
+ tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
+ tmptup.t_data = td;
+
+ tup = heap_copytuple(&tmptup);
+
+ ReleaseSysCache(htup);
+
+ return tup;
+}
+
+/*
+ * Evaluate the expressions, so that we can use the results to build
+ * all the requested statistics types. This matters especially for
+ * expensive expressions, of course.
+ */
+static ExprInfo *
+evaluate_expressions(Relation rel, List *exprs, int numrows, HeapTuple *rows)
+{
+ /* evaluated expressions */
+ ExprInfo *result;
+ char *ptr;
+ Size len;
+
+ int i;
+ int idx;
+ TupleTableSlot *slot;
+ EState *estate;
+ ExprContext *econtext;
+ List *exprstates = NIL;
+ int nexprs = list_length(exprs);
+ ListCell *lc;
+
+ /* allocate everything as a single chunk, so we can free it easily */
+ len = MAXALIGN(sizeof(ExprInfo));
+ len += MAXALIGN(sizeof(Oid) * nexprs); /* types */
+ len += MAXALIGN(sizeof(Oid) * nexprs); /* collations */
+
+ /* values */
+ len += MAXALIGN(sizeof(Datum *) * nexprs);
+ len += nexprs * MAXALIGN(sizeof(Datum) * numrows);
+
+ /* nulls */
+ len += MAXALIGN(sizeof(bool *) * nexprs);
+ len += nexprs * MAXALIGN(sizeof(bool) * numrows);
+
+ ptr = palloc(len);
+
+ /* set the pointers */
+ result = (ExprInfo *) ptr;
+ ptr += MAXALIGN(sizeof(ExprInfo));
+
+ /* types */
+ result->types = (Oid *) ptr;
+ ptr += MAXALIGN(sizeof(Oid) * nexprs);
+
+ /* collations */
+ result->collations = (Oid *) ptr;
+ ptr += MAXALIGN(sizeof(Oid) * nexprs);
+
+ /* values */
+ result->values = (Datum **) ptr;
+ ptr += MAXALIGN(sizeof(Datum *) * nexprs);
+
+ /* nulls */
+ result->nulls = (bool **) ptr;
+ ptr += MAXALIGN(sizeof(bool *) * nexprs);
+
+ for (i = 0; i < nexprs; i++)
+ {
+ result->values[i] = (Datum *) ptr;
+ ptr += MAXALIGN(sizeof(Datum) * numrows);
+
+ result->nulls[i] = (bool *) ptr;
+ ptr += MAXALIGN(sizeof(bool) * numrows);
+ }
+
+ Assert((ptr - (char *) result) == len);
+
+ result->nexprs = list_length(exprs);
+
+ idx = 0;
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+
+ result->types[idx] = exprType(expr);
+ result->collations[idx] = exprCollation(expr);
+
+ idx++;
+ }
+
+ /*
+ * Need an EState for evaluation of index expressions and
+ * partial-index predicates. Create it in the per-index context to be
+ * sure it gets cleaned up at the bottom of the loop.
+ */
+ estate = CreateExecutorState();
+ econtext = GetPerTupleExprContext(estate);
+
+ /* Need a slot to hold the current heap tuple, too */
+ slot = MakeSingleTupleTableSlot(RelationGetDescr(rel),
+ &TTSOpsHeapTuple);
+
+ /* Arrange for econtext's scan tuple to be the tuple under test */
+ econtext->ecxt_scantuple = slot;
+
+ /* Set up expression evaluation state */
+ exprstates = ExecPrepareExprList(exprs, estate);
+
+ for (i = 0; i < numrows; i++)
+ {
+ /*
+ * Reset the per-tuple context each time, to reclaim any cruft
+ * left behind by evaluating the predicate or index expressions.
+ */
+ ResetExprContext(econtext);
+
+ /* Set up for predicate or expression evaluation */
+ ExecStoreHeapTuple(rows[i], slot, false);
+
+ idx = 0;
+ foreach (lc, exprstates)
+ {
+ Datum datum;
+ bool isnull;
+ ExprState *exprstate = (ExprState *) lfirst(lc);
+
+ /*
+ * FIXME this probably leaks memory. Maybe we should use
+ * ExecEvalExprSwitchContext but then we need to copy the
+ * result somewhere else.
+ */
+ datum = ExecEvalExpr(exprstate,
+ GetPerTupleExprContext(estate),
+ &isnull);
+ if (isnull)
+ {
+ result->values[idx][i] = (Datum) 0;
+ result->nulls[idx][i] = true;
+ }
+ else
+ {
+ result->values[idx][i] = (Datum) datum;
+ result->nulls[idx][i] = false;
+ }
+
+ idx++;
+ }
+ }
+
+ ExecDropSingleTupleTableSlot(slot);
+ FreeExecutorState(estate);
+
+ return result;
+}
+
+/*
+ * add_expressions_to_attributes
+ * add expressions as attributes with high attnums
+ *
+ * Treat the expressions as attributes with attnums above the regular
+ * attnum range. This will allow us to handle everything in the same
+ * way, and identify expressions in the dependencies.
+ *
+ * XXX This always creates a copy of the bitmap. We might optimize this
+ * by only creating the copy with (nexprs > 0) but then we'd have to track
+ * this in order to free it (if we want to). Does not seem worth it.
+ */
+Bitmapset *
+add_expressions_to_attributes(Bitmapset *attrs, int nexprs)
+{
+ int i;
+
+ /*
+ * Copy the bitmapset and add fake attnums representing expressions,
+ * starting above MaxHeapAttributeNumber.
+ */
+ attrs = bms_copy(attrs);
+
+ /* start with (MaxHeapAttributeNumber + 1) */
+ for (i = 0; i < nexprs; i++)
+ {
+ Assert(EXPRESSION_ATTNUM(i) > MaxHeapAttributeNumber);
+
+ attrs = bms_add_member(attrs, EXPRESSION_ATTNUM(i));
+ }
+
+ return attrs;
+}
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index abbc1f1ba8..0c27ee395e 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -74,7 +74,8 @@
((ndims) * sizeof(DimensionInfo)) + \
((nitems) * ITEM_SIZE(ndims)))
-static MultiSortSupport build_mss(VacAttrStats **stats, int numattrs);
+static MultiSortSupport build_mss(VacAttrStats **stats, int numattrs,
+ ExprInfo *exprs);
static SortItem *build_distinct_groups(int numrows, SortItem *items,
MultiSortSupport mss, int *ndistinct);
@@ -181,8 +182,9 @@ get_mincount_for_mcv_list(int samplerows, double totalrows)
*
*/
MCVList *
-statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
- VacAttrStats **stats, double totalrows, int stattarget)
+statext_mcv_build(int numrows, HeapTuple *rows, ExprInfo *exprs,
+ Bitmapset *attrs, VacAttrStats **stats,
+ double totalrows, int stattarget)
{
int i,
numattrs,
@@ -195,14 +197,23 @@ statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
MCVList *mcvlist = NULL;
MultiSortSupport mss;
- attnums = build_attnums_array(attrs, &numattrs);
-
/* comparator for all the columns */
- mss = build_mss(stats, numattrs);
+ mss = build_mss(stats, bms_num_members(attrs), exprs);
+
+ /*
+ * treat expressions as special attributes with high attnums
+ *
+ * XXX We do this after build_mss, because that expects the bitmapset
+ * to only contain simple attributes (with a matching VacAttrStats)
+ */
+ attrs = add_expressions_to_attributes(attrs, exprs->nexprs);
+
+ /* now build the array, with the special expression attnums */
+ attnums = build_attnums_array(attrs, &numattrs);
/* sort the rows */
- items = build_sorted_items(numrows, &nitems, rows, stats[0]->tupDesc,
- mss, numattrs, attnums);
+ items = build_sorted_items(numrows, &nitems, rows, exprs,
+ stats[0]->tupDesc, mss, numattrs, attnums);
if (!items)
return NULL;
@@ -338,6 +349,7 @@ statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
pfree(items);
pfree(groups);
+ pfree(attrs);
return mcvlist;
}
@@ -347,12 +359,12 @@ statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
* build MultiSortSupport for the attributes passed in attrs
*/
static MultiSortSupport
-build_mss(VacAttrStats **stats, int numattrs)
+build_mss(VacAttrStats **stats, int numattrs, ExprInfo *exprs)
{
int i;
/* Sort by multiple columns (using array of SortSupport) */
- MultiSortSupport mss = multi_sort_init(numattrs);
+ MultiSortSupport mss = multi_sort_init(numattrs + exprs->nexprs);
/* prepare the sort functions for all the attributes */
for (i = 0; i < numattrs; i++)
@@ -368,6 +380,20 @@ build_mss(VacAttrStats **stats, int numattrs)
multi_sort_add_dimension(mss, i, type->lt_opr, colstat->attrcollid);
}
+ /* prepare the sort functions for all the expressions */
+ for (i = 0; i < exprs->nexprs; i++)
+ {
+ TypeCacheEntry *type;
+
+ type = lookup_type_cache(exprs->types[i], TYPECACHE_LT_OPR);
+ if (type->lt_opr == InvalidOid) /* shouldn't happen */
+ elog(ERROR, "cache lookup failed for ordering operator for type %u",
+ exprs->types[i]);
+
+ multi_sort_add_dimension(mss, numattrs + i, type->lt_opr,
+ exprs->collations[i]);
+ }
+
return mss;
}
@@ -570,7 +596,7 @@ statext_mcv_load(Oid mvoid)
if (isnull)
elog(ERROR,
- "requested statistic kind \"%c\" is not yet built for statistics object %u",
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
STATS_EXT_DEPENDENCIES, mvoid);
result = statext_mcv_deserialize(DatumGetByteaP(mcvlist));
@@ -1541,10 +1567,14 @@ pg_mcv_list_send(PG_FUNCTION_ARGS)
* the size to ~1/8. It would also allow us to combine bitmaps simply using
* & and |, which should be faster than min/max. The bitmaps are fairly
* small, though (thanks to the cap on the MCV list size).
+ *
+ * XXX There's a lot of code duplication between branches for simple columns
+ * and complex expressions. We should refactor it somehow.
*/
static bool *
mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
- Bitmapset *keys, MCVList *mcvlist, bool is_or)
+ Bitmapset *keys, List *exprs,
+ MCVList *mcvlist, bool is_or)
{
int i;
ListCell *l;
@@ -1584,8 +1614,10 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
/* valid only after examine_clause_args returns true */
Var *var;
+ Node *clause_expr;
Const *cst;
bool varonleft;
+ bool expronleft;
fmgr_info(get_opcode(expr->opno), &opproc);
@@ -1654,6 +1686,89 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
matches[i] = RESULT_MERGE(matches[i], is_or, match);
}
}
+ /* extract the expr and const from the expression */
+ else if (examine_clause_args2(expr->args, &clause_expr, &cst, &expronleft))
+ {
+ ListCell *lc;
+ int idx;
+ Oid collid = exprCollation(clause_expr);
+
+ /* match the attribute to a dimension of the statistic */
+ idx = bms_num_members(keys);
+
+ foreach(lc, exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ if (equal(clause_expr, stat_expr))
+ break;
+
+ idx++;
+ }
+
+ /* index should be valid */
+ Assert((idx >= 0) &&
+ (idx < bms_num_members(keys) + list_length(exprs)));
+
+ /*
+ * Walk through the MCV items and evaluate the current clause.
+ * We can skip items that were already ruled out, and
+ * terminate if there are no remaining MCV items that might
+ * possibly match.
+ */
+ for (i = 0; i < mcvlist->nitems; i++)
+ {
+ bool match = true;
+ MCVItem *item = &mcvlist->items[i];
+
+ /*
+ * When the MCV item or the Const value is NULL we can
+ * treat this as a mismatch. We must not call the operator
+ * because of strictness.
+ */
+ if (item->isnull[idx] || cst->constisnull)
+ {
+ matches[i] = RESULT_MERGE(matches[i], is_or, false);
+ continue;
+ }
+
+ /*
+ * Skip MCV items that can't change result in the bitmap.
+ * Once the value gets false for AND-lists, or true for
+ * OR-lists, we don't need to look at more clauses.
+ */
+ if (RESULT_IS_FINAL(matches[i], is_or))
+ continue;
+
+ /*
+ * First check whether the constant is below the lower
+ * boundary (in that case we can skip the bucket, because
+ * there's no overlap).
+ *
+ * We don't store collations used to build the statistics,
+ * but we can use the collation for the attribute itself,
+ * as stored in varcollid. We do reset the statistics
+ * after a type change (including collation change), so
+ * this is OK. We may need to relax this after allowing
+ * extended statistics on expressions.
+ */
+ if (expronleft)
+ match = DatumGetBool(FunctionCall2Coll(&opproc,
+ collid,
+ item->values[idx],
+ cst->constvalue));
+ else
+ match = DatumGetBool(FunctionCall2Coll(&opproc,
+ collid,
+ cst->constvalue,
+ item->values[idx]));
+
+ /* update the match bitmap with the result */
+ matches[i] = RESULT_MERGE(matches[i], is_or, match);
+ }
+ }
+ else
+ elog(ERROR, "incompatible clause");
}
else if (IsA(clause, ScalarArrayOpExpr))
{
@@ -1662,8 +1777,10 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
/* valid only after examine_clause_args returns true */
Var *var;
+ Node *clause_expr;
Const *cst;
bool varonleft;
+ bool expronleft;
fmgr_info(get_opcode(expr->opno), &opproc);
@@ -1761,14 +1878,155 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
matches[i] = RESULT_MERGE(matches[i], is_or, match);
}
}
+ /* extract the expr and const from the expression */
+ else if (examine_clause_args2(expr->args, &clause_expr, &cst, &expronleft))
+ {
+ ListCell *lc;
+ int idx;
+
+ ArrayType *arrayval;
+ int16 elmlen;
+ bool elmbyval;
+ char elmalign;
+ int num_elems;
+ Datum *elem_values;
+ bool *elem_nulls;
+ Oid collid = exprCollation(clause_expr);
+
+ /* ScalarArrayOpExpr has the Var always on the left */
+ Assert(expronleft);
+
+ if (!cst->constisnull)
+ {
+ arrayval = DatumGetArrayTypeP(cst->constvalue);
+ get_typlenbyvalalign(ARR_ELEMTYPE(arrayval),
+ &elmlen, &elmbyval, &elmalign);
+ deconstruct_array(arrayval,
+ ARR_ELEMTYPE(arrayval),
+ elmlen, elmbyval, elmalign,
+ &elem_values, &elem_nulls, &num_elems);
+ }
+
+ /* match the attribute to a dimension of the statistic */
+ idx = bms_num_members(keys);
+
+ foreach(lc, exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ if (equal(clause_expr, stat_expr))
+ break;
+
+ idx++;
+ }
+
+ /* index should be valid */
+ Assert((idx >= 0) &&
+ (idx < bms_num_members(keys) + list_length(exprs)));
+
+ /*
+ * Walk through the MCV items and evaluate the current clause.
+ * We can skip items that were already ruled out, and
+ * terminate if there are no remaining MCV items that might
+ * possibly match.
+ */
+ for (i = 0; i < mcvlist->nitems; i++)
+ {
+ int j;
+ bool match = (expr->useOr ? false : true);
+ MCVItem *item = &mcvlist->items[i];
+
+ /*
+ * When the MCV item or the Const value is NULL we can
+ * treat this as a mismatch. We must not call the operator
+ * because of strictness.
+ */
+ if (item->isnull[idx] || cst->constisnull)
+ {
+ matches[i] = RESULT_MERGE(matches[i], is_or, false);
+ continue;
+ }
+
+ /*
+ * Skip MCV items that can't change result in the bitmap.
+ * Once the value gets false for AND-lists, or true for
+ * OR-lists, we don't need to look at more clauses.
+ */
+ if (RESULT_IS_FINAL(matches[i], is_or))
+ continue;
+
+ for (j = 0; j < num_elems; j++)
+ {
+ Datum elem_value = elem_values[j];
+ bool elem_isnull = elem_nulls[j];
+ bool elem_match;
+
+ /* NULL values always evaluate as not matching. */
+ if (elem_isnull)
+ {
+ match = RESULT_MERGE(match, expr->useOr, false);
+ continue;
+ }
+
+ /*
+ * Stop evaluating the array elements once we reach
+ * match value that can't change - ALL() is the same
+ * as AND-list, ANY() is the same as OR-list.
+ */
+ if (RESULT_IS_FINAL(match, expr->useOr))
+ break;
+
+ elem_match = DatumGetBool(FunctionCall2Coll(&opproc,
+ collid,
+ item->values[idx],
+ elem_value));
+
+ match = RESULT_MERGE(match, expr->useOr, elem_match);
+ }
+
+ /* update the match bitmap with the result */
+ matches[i] = RESULT_MERGE(matches[i], is_or, match);
+ }
+ }
+ else
+ elog(ERROR, "incompatible clause");
}
else if (IsA(clause, NullTest))
{
NullTest *expr = (NullTest *) clause;
- Var *var = (Var *) (expr->arg);
+ Node *clause_expr = (Node *) (expr->arg);
/* match the attribute to a dimension of the statistic */
- int idx = bms_member_index(keys, var->varattno);
+ int idx = -1;
+
+ if (IsA(clause_expr, Var))
+ {
+ /* simple Var, so just lookup using varattno */
+ Var *var = (Var *) clause_expr;
+
+ idx = bms_member_index(keys, var->varattno);
+ }
+ else
+ {
+ ListCell *lc;
+
+ /* expressions are after the simple columns */
+ idx = bms_num_members(keys);
+
+ /* expression - lookup in stats expressions */
+ foreach(lc, exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ if (equal(clause_expr, stat_expr))
+ break;
+
+ idx++;
+ }
+ }
+
+ /* index should be valid */
+ Assert((idx >= 0) && (idx < bms_num_members(keys) + list_length(exprs)));
/*
* Walk through the MCV items and evaluate the current clause. We
@@ -1811,7 +2069,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
Assert(list_length(bool_clauses) >= 2);
/* build the match bitmap for the OR-clauses */
- bool_matches = mcv_get_match_bitmap(root, bool_clauses, keys,
+ bool_matches = mcv_get_match_bitmap(root, bool_clauses, keys, exprs,
mcvlist, is_orclause(clause));
/*
@@ -1839,7 +2097,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
Assert(list_length(not_args) == 1);
/* build the match bitmap for the NOT-clause */
- not_matches = mcv_get_match_bitmap(root, not_args, keys,
+ not_matches = mcv_get_match_bitmap(root, not_args, keys, exprs,
mcvlist, false);
/*
@@ -1982,7 +2240,8 @@ mcv_clauselist_selectivity(PlannerInfo *root, StatisticExtInfo *stat,
mcv = statext_mcv_load(stat->statOid);
/* build a match bitmap for the clauses */
- matches = mcv_get_match_bitmap(root, clauses, stat->keys, mcv, false);
+ matches = mcv_get_match_bitmap(root, clauses, stat->keys, stat->exprs,
+ mcv, false);
/* sum frequencies for all the matching MCV items */
*basesel = 0.0;
@@ -2056,7 +2315,7 @@ mcv_clause_selectivity_or(PlannerInfo *root, StatisticExtInfo *stat,
/* build the match bitmap for the new clause */
new_matches = mcv_get_match_bitmap(root, list_make1(clause), stat->keys,
- mcv, false);
+ stat->exprs, mcv, false);
/*
* Sum the frequencies for all the MCV items matching this clause and also
diff --git a/src/backend/statistics/mvdistinct.c b/src/backend/statistics/mvdistinct.c
index 9ef21debb6..55d3fa0e1f 100644
--- a/src/backend/statistics/mvdistinct.c
+++ b/src/backend/statistics/mvdistinct.c
@@ -37,7 +37,8 @@
#include "utils/typcache.h"
static double ndistinct_for_combination(double totalrows, int numrows,
- HeapTuple *rows, VacAttrStats **stats,
+ HeapTuple *rows, ExprInfo *exprs,
+ int nattrs, VacAttrStats **stats,
int k, int *combination);
static double estimate_ndistinct(double totalrows, int numrows, int d, int f1);
static int n_choose_k(int n, int k);
@@ -81,16 +82,21 @@ static void generate_combinations(CombinationGenerator *state);
*
* This computes the ndistinct estimate using the same estimator used
* in analyze.c and then computes the coefficient.
+ *
+ * To handle expressions easily, we treat them as special attributes with
+ * attnums above MaxHeapAttributeNumber, and we assume the expressions are
+ * placed after all simple attributes.
*/
MVNDistinct *
statext_ndistinct_build(double totalrows, int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats)
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats)
{
MVNDistinct *result;
int k;
int itemcnt;
int numattrs = bms_num_members(attrs);
- int numcombs = num_combinations(numattrs);
+ int numcombs = num_combinations(numattrs + exprs->nexprs);
result = palloc(offsetof(MVNDistinct, items) +
numcombs * sizeof(MVNDistinctItem));
@@ -98,14 +104,20 @@ statext_ndistinct_build(double totalrows, int numrows, HeapTuple *rows,
result->type = STATS_NDISTINCT_TYPE_BASIC;
result->nitems = numcombs;
+ /* treat expressions as special attributes with high attnums */
+ attrs = add_expressions_to_attributes(attrs, exprs->nexprs);
+
+ /* make sure there were no clashes */
+ Assert(bms_num_members(attrs) == numattrs + exprs->nexprs);
+
itemcnt = 0;
- for (k = 2; k <= numattrs; k++)
+ for (k = 2; k <= bms_num_members(attrs); k++)
{
int *combination;
CombinationGenerator *generator;
/* generate combinations of K out of N elements */
- generator = generator_init(numattrs, k);
+ generator = generator_init(bms_num_members(attrs), k);
while ((combination = generator_next(generator)))
{
@@ -114,10 +126,32 @@ statext_ndistinct_build(double totalrows, int numrows, HeapTuple *rows,
item->attrs = NULL;
for (j = 0; j < k; j++)
- item->attrs = bms_add_member(item->attrs,
- stats[combination[j]]->attr->attnum);
+ {
+ AttrNumber attnum = InvalidAttrNumber;
+
+ /*
+ * The simple attributes are before expressions, so have
+ * indexes below numattrs.
+ * */
+ if (combination[j] < numattrs)
+ attnum = stats[combination[j]]->attr->attnum;
+ else
+ {
+ /* make sure the expression index is valid */
+ Assert((combination[j] - numattrs) >= 0);
+ Assert((combination[j] - numattrs) < exprs->nexprs);
+
+ attnum = EXPRESSION_ATTNUM(combination[j] - numattrs);
+ }
+
+ Assert(attnum != InvalidAttrNumber);
+
+ item->attrs = bms_add_member(item->attrs, attnum);
+ }
+
item->ndistinct =
ndistinct_for_combination(totalrows, numrows, rows,
+ exprs, numattrs,
stats, k, combination);
itemcnt++;
@@ -153,7 +187,7 @@ statext_ndistinct_load(Oid mvoid)
Anum_pg_statistic_ext_data_stxdndistinct, &isnull);
if (isnull)
elog(ERROR,
- "requested statistic kind \"%c\" is not yet built for statistics object %u",
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
STATS_EXT_NDISTINCT, mvoid);
result = statext_ndistinct_deserialize(DatumGetByteaPP(ndist));
@@ -428,6 +462,7 @@ pg_ndistinct_send(PG_FUNCTION_ARGS)
*/
static double
ndistinct_for_combination(double totalrows, int numrows, HeapTuple *rows,
+ ExprInfo *exprs, int nattrs,
VacAttrStats **stats, int k, int *combination)
{
int i,
@@ -467,25 +502,57 @@ ndistinct_for_combination(double totalrows, int numrows, HeapTuple *rows,
*/
for (i = 0; i < k; i++)
{
- VacAttrStats *colstat = stats[combination[i]];
+ Oid typid;
TypeCacheEntry *type;
+ AttrNumber attnum = InvalidAttrNumber;
+ TupleDesc tdesc = NULL;
+ Oid collid = InvalidOid;
+
+ if (combination[i] < nattrs)
+ {
+ VacAttrStats *colstat = stats[combination[i]];
+ typid = colstat->attrtypid;
+ attnum = colstat->attr->attnum;
+ collid = colstat->attrcollid;
+ tdesc = colstat->tupDesc;
+ }
+ else
+ {
+ typid = exprs->types[combination[i] - nattrs];
+ collid = exprs->collations[combination[i] - nattrs];
+ }
- type = lookup_type_cache(colstat->attrtypid, TYPECACHE_LT_OPR);
+ type = lookup_type_cache(typid, TYPECACHE_LT_OPR);
if (type->lt_opr == InvalidOid) /* shouldn't happen */
elog(ERROR, "cache lookup failed for ordering operator for type %u",
- colstat->attrtypid);
+ typid);
/* prepare the sort function for this dimension */
- multi_sort_add_dimension(mss, i, type->lt_opr, colstat->attrcollid);
+ multi_sort_add_dimension(mss, i, type->lt_opr, collid);
/* accumulate all the data for this dimension into the arrays */
for (j = 0; j < numrows; j++)
{
- items[j].values[i] =
- heap_getattr(rows[j],
- colstat->attr->attnum,
- colstat->tupDesc,
- &items[j].isnull[i]);
+ /*
+ * The first nattrs indexes identify simple attributes, higher
+ * indexes are expressions.
+ */
+ if (combination[i] < nattrs)
+ items[j].values[i] =
+ heap_getattr(rows[j],
+ attnum,
+ tdesc,
+ &items[j].isnull[i]);
+ else
+ {
+ int idx = (combination[i] - nattrs);
+
+ /* make sure the expression index is valid */
+ Assert((idx >= 0) && (idx < exprs->nexprs));
+
+ items[j].values[i] = exprs->values[idx][j];
+ items[j].isnull[i] = exprs->nulls[idx][j];
+ }
}
}
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 1d81071c35..eb0c030025 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -1796,7 +1796,28 @@ ProcessUtilitySlow(ParseState *pstate,
break;
case T_CreateStatsStmt:
- address = CreateStatistics((CreateStatsStmt *) parsetree);
+ {
+ Oid relid;
+ CreateStatsStmt *stmt = (CreateStatsStmt *) parsetree;
+ RangeVar *rel = (RangeVar *) linitial(stmt->relations);
+
+ /*
+ * CREATE STATISTICS will influence future execution plans
+ * but does not interfere with currently executing plans.
+ * So it should be enough to take ShareUpdateExclusiveLock
+ * on relation, conflicting with ANALYZE and other DDL that
+ * sets statistical information, but not with normal queries.
+ *
+ * XXX RangeVarCallbackOwnsRelation not needed needed here,
+ * to keep the same behavior as before.
+ */
+ relid = RangeVarGetRelid(rel, ShareUpdateExclusiveLock, false);
+
+ /* Run parse analysis ... */
+ stmt = transformStatsStmt(relid, stmt, queryString);
+
+ address = CreateStatistics(stmt);
+ }
break;
case T_AlterStatsStmt:
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 8a1fbda572..7d08d752a1 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -336,7 +336,8 @@ static char *pg_get_indexdef_worker(Oid indexrelid, int colno,
bool attrsOnly, bool keysOnly,
bool showTblSpc, bool inherits,
int prettyFlags, bool missing_ok);
-static char *pg_get_statisticsobj_worker(Oid statextid, bool missing_ok);
+static char *pg_get_statisticsobj_worker(Oid statextid, bool columns_only,
+ bool missing_ok);
static char *pg_get_partkeydef_worker(Oid relid, int prettyFlags,
bool attrsOnly, bool missing_ok);
static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
@@ -1507,7 +1508,26 @@ pg_get_statisticsobjdef(PG_FUNCTION_ARGS)
Oid statextid = PG_GETARG_OID(0);
char *res;
- res = pg_get_statisticsobj_worker(statextid, true);
+ res = pg_get_statisticsobj_worker(statextid, false, true);
+
+ if (res == NULL)
+ PG_RETURN_NULL();
+
+ PG_RETURN_TEXT_P(string_to_text(res));
+}
+
+
+/*
+ * pg_get_statisticsobjdef_columns
+ * Get columns and expressions for an extended statistics object
+ */
+Datum
+pg_get_statisticsobjdef_columns(PG_FUNCTION_ARGS)
+{
+ Oid statextid = PG_GETARG_OID(0);
+ char *res;
+
+ res = pg_get_statisticsobj_worker(statextid, true, true);
if (res == NULL)
PG_RETURN_NULL();
@@ -1519,7 +1539,7 @@ pg_get_statisticsobjdef(PG_FUNCTION_ARGS)
* Internal workhorse to decompile an extended statistics object.
*/
static char *
-pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
+pg_get_statisticsobj_worker(Oid statextid, bool columns_only, bool missing_ok)
{
Form_pg_statistic_ext statextrec;
HeapTuple statexttup;
@@ -1534,6 +1554,11 @@ pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
bool dependencies_enabled;
bool mcv_enabled;
int i;
+ List *context;
+ ListCell *lc;
+ List *exprs = NIL;
+ bool has_exprs;
+ int ncolumns;
statexttup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statextid));
@@ -1544,75 +1569,112 @@ pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
elog(ERROR, "cache lookup failed for statistics object %u", statextid);
}
- statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
-
- initStringInfo(&buf);
+ /* has the statistics expressions? */
+ has_exprs = !heap_attisnull(statexttup, Anum_pg_statistic_ext_stxexprs, NULL);
- nsp = get_namespace_name(statextrec->stxnamespace);
- appendStringInfo(&buf, "CREATE STATISTICS %s",
- quote_qualified_identifier(nsp,
- NameStr(statextrec->stxname)));
+ statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
/*
- * Decode the stxkind column so that we know which stats types to print.
+ * Get the statistics expressions, if any. (NOTE: we do not use the
+ * relcache versions of the expressions and predicate, because we want
+ * to display non-const-folded expressions.)
*/
- datum = SysCacheGetAttr(STATEXTOID, statexttup,
- Anum_pg_statistic_ext_stxkind, &isnull);
- Assert(!isnull);
- arr = DatumGetArrayTypeP(datum);
- if (ARR_NDIM(arr) != 1 ||
- ARR_HASNULL(arr) ||
- ARR_ELEMTYPE(arr) != CHAROID)
- elog(ERROR, "stxkind is not a 1-D char array");
- enabled = (char *) ARR_DATA_PTR(arr);
-
- ndistinct_enabled = false;
- dependencies_enabled = false;
- mcv_enabled = false;
-
- for (i = 0; i < ARR_DIMS(arr)[0]; i++)
+ if (has_exprs)
{
- if (enabled[i] == STATS_EXT_NDISTINCT)
- ndistinct_enabled = true;
- if (enabled[i] == STATS_EXT_DEPENDENCIES)
- dependencies_enabled = true;
- if (enabled[i] == STATS_EXT_MCV)
- mcv_enabled = true;
+ Datum exprsDatum;
+ bool isnull;
+ char *exprsString;
+
+ exprsDatum = SysCacheGetAttr(STATEXTOID, statexttup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+ Assert(!isnull);
+ exprsString = TextDatumGetCString(exprsDatum);
+ exprs = (List *) stringToNode(exprsString);
+ pfree(exprsString);
}
+ else
+ exprs = NIL;
- /*
- * If any option is disabled, then we'll need to append the types clause
- * to show which options are enabled. We omit the types clause on purpose
- * when all options are enabled, so a pg_dump/pg_restore will create all
- * statistics types on a newer postgres version, if the statistics had all
- * options enabled on the original version.
- */
- if (!ndistinct_enabled || !dependencies_enabled || !mcv_enabled)
+ /* count the number of columns (attributes and expressions) */
+ ncolumns = statextrec->stxkeys.dim1 + list_length(exprs);
+
+ initStringInfo(&buf);
+
+ if (!columns_only)
{
- bool gotone = false;
+ nsp = get_namespace_name(statextrec->stxnamespace);
+ appendStringInfo(&buf, "CREATE STATISTICS %s",
+ quote_qualified_identifier(nsp,
+ NameStr(statextrec->stxname)));
- appendStringInfoString(&buf, " (");
+ /*
+ * Decode the stxkind column so that we know which stats types to print.
+ */
+ datum = SysCacheGetAttr(STATEXTOID, statexttup,
+ Anum_pg_statistic_ext_stxkind, &isnull);
+ Assert(!isnull);
+ arr = DatumGetArrayTypeP(datum);
+ if (ARR_NDIM(arr) != 1 ||
+ ARR_HASNULL(arr) ||
+ ARR_ELEMTYPE(arr) != CHAROID)
+ elog(ERROR, "stxkind is not a 1-D char array");
+ enabled = (char *) ARR_DATA_PTR(arr);
+
+ ndistinct_enabled = false;
+ dependencies_enabled = false;
+ mcv_enabled = false;
- if (ndistinct_enabled)
+ for (i = 0; i < ARR_DIMS(arr)[0]; i++)
{
- appendStringInfoString(&buf, "ndistinct");
- gotone = true;
+ if (enabled[i] == STATS_EXT_NDISTINCT)
+ ndistinct_enabled = true;
+ else if (enabled[i] == STATS_EXT_DEPENDENCIES)
+ dependencies_enabled = true;
+ else if (enabled[i] == STATS_EXT_MCV)
+ mcv_enabled = true;
+
+ /* ignore STATS_EXT_EXPRESSIONS (it's built automatically) */
}
- if (dependencies_enabled)
+ /*
+ * If any option is disabled, then we'll need to append the types clause
+ * to show which options are enabled. We omit the types clause on purpose
+ * when all options are enabled, so a pg_dump/pg_restore will create all
+ * statistics types on a newer postgres version, if the statistics had all
+ * options enabled on the original version.
+ *
+ * But if the statistics is defined on just a single column, it has to be
+ * an expression statistics. In that case we don't need to specify kinds.
+ */
+ if ((!ndistinct_enabled || !dependencies_enabled || !mcv_enabled) &&
+ (ncolumns > 1))
{
- appendStringInfo(&buf, "%sdependencies", gotone ? ", " : "");
- gotone = true;
- }
+ bool gotone = false;
- if (mcv_enabled)
- appendStringInfo(&buf, "%smcv", gotone ? ", " : "");
+ appendStringInfoString(&buf, " (");
- appendStringInfoChar(&buf, ')');
- }
+ if (ndistinct_enabled)
+ {
+ appendStringInfoString(&buf, "ndistinct");
+ gotone = true;
+ }
+
+ if (dependencies_enabled)
+ {
+ appendStringInfo(&buf, "%sdependencies", gotone ? ", " : "");
+ gotone = true;
+ }
- appendStringInfoString(&buf, " ON ");
+ if (mcv_enabled)
+ appendStringInfo(&buf, "%smcv", gotone ? ", " : "");
+ appendStringInfoChar(&buf, ')');
+ }
+
+ appendStringInfoString(&buf, " ON ");
+ }
+
+ /* decode simple column references */
for (colno = 0; colno < statextrec->stxkeys.dim1; colno++)
{
AttrNumber attnum = statextrec->stxkeys.values[colno];
@@ -1626,14 +1688,109 @@ pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
appendStringInfoString(&buf, quote_identifier(attname));
}
- appendStringInfo(&buf, " FROM %s",
- generate_relation_name(statextrec->stxrelid, NIL));
+ context = deparse_context_for(get_relation_name(statextrec->stxrelid),
+ statextrec->stxrelid);
+
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+ char *str;
+ int prettyFlags = PRETTYFLAG_INDENT;
+
+ str = deparse_expression_pretty(expr, context, false, false,
+ prettyFlags, 0);
+
+ if (colno > 0)
+ appendStringInfoString(&buf, ", ");
+
+ /* Need parens if it's not a bare function call */
+ if (looks_like_function(expr))
+ appendStringInfoString(&buf, str);
+ else
+ appendStringInfo(&buf, "(%s)", str);
+
+ colno++;
+ }
+
+ if (!columns_only)
+ appendStringInfo(&buf, " FROM %s",
+ generate_relation_name(statextrec->stxrelid, NIL));
ReleaseSysCache(statexttup);
return buf.data;
}
+/*
+ * Generate text array of expressions for statistics object.
+ */
+Datum
+pg_get_statisticsobjdef_expressions(PG_FUNCTION_ARGS)
+{
+ Oid statextid = PG_GETARG_OID(0);
+ Form_pg_statistic_ext statextrec;
+ HeapTuple statexttup;
+ Datum datum;
+ bool isnull;
+ List *context;
+ ListCell *lc;
+ List *exprs = NIL;
+ bool has_exprs;
+ char *tmp;
+ ArrayBuildState *astate = NULL;
+
+ statexttup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statextid));
+
+ if (!HeapTupleIsValid(statexttup))
+ elog(ERROR, "cache lookup failed for statistics object %u", statextid);
+
+ /* has the statistics expressions? */
+ has_exprs = !heap_attisnull(statexttup, Anum_pg_statistic_ext_stxexprs, NULL);
+
+ /* no expressions? we're done */
+ if (!has_exprs)
+ {
+ ReleaseSysCache(statexttup);
+ PG_RETURN_NULL();
+ }
+
+ statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
+
+ /*
+ * Get the statistics expressions, and deparse them into text values.
+ */
+ datum = SysCacheGetAttr(STATEXTOID, statexttup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ Assert(!isnull);
+ tmp = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(tmp);
+ pfree(tmp);
+
+ context = deparse_context_for(get_relation_name(statextrec->stxrelid),
+ statextrec->stxrelid);
+
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+ char *str;
+ int prettyFlags = PRETTYFLAG_INDENT;
+
+ str = deparse_expression_pretty(expr, context, false, false,
+ prettyFlags, 0);
+
+ astate = accumArrayResult(astate,
+ PointerGetDatum(cstring_to_text(str)),
+ false,
+ TEXTOID,
+ CurrentMemoryContext);
+ }
+
+ ReleaseSysCache(statexttup);
+
+ PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
+}
+
/*
* pg_get_partkeydef
*
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index d5e61664bc..bfe3dfb93b 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -3291,6 +3291,88 @@ add_unique_group_var(PlannerInfo *root, List *varinfos,
return varinfos;
}
+/*
+ * Helper routine for estimate_num_groups: add an item to a list of
+ * GroupExprInfos, but only if it's not known equal to any of the existing
+ * entries.
+ */
+typedef struct
+{
+ Node *expr; /* expression */
+ RelOptInfo *rel; /* relation it belongs to */
+ List *varinfos; /* info for variables in this expression */
+} GroupExprInfo;
+
+static List *
+add_unique_group_expr(PlannerInfo *root, List *exprinfos,
+ Node *expr, List *vars)
+{
+ GroupExprInfo *exprinfo;
+ ListCell *lc;
+ Bitmapset *varnos;
+ Index varno;
+
+ foreach(lc, exprinfos)
+ {
+ exprinfo = (GroupExprInfo *) lfirst(lc);
+
+ /* Drop exact duplicates */
+ if (equal(expr, exprinfo->expr))
+ return exprinfos;
+ }
+
+ exprinfo = (GroupExprInfo *) palloc(sizeof(GroupExprInfo));
+
+ varnos = pull_varnos(expr);
+
+ /*
+ * Expressions with vars from multiple relations should never get
+ * here, as we split them to vars.
+ */
+ Assert(bms_num_members(varnos) == 1);
+
+ varno = bms_singleton_member(varnos);
+
+ exprinfo->expr = expr;
+ exprinfo->varinfos = NIL;
+ exprinfo->rel = root->simple_rel_array[varno];
+
+ Assert(exprinfo->rel);
+
+ /* Track vars for this expression. */
+ foreach (lc, vars)
+ {
+ VariableStatData vardata;
+ Node *var = (Node *) lfirst(lc);
+
+ /* can we get no vardata for the variable? */
+ examine_variable(root, var, 0, &vardata);
+
+ exprinfo->varinfos
+ = add_unique_group_var(root, exprinfo->varinfos, var, &vardata);
+
+ ReleaseVariableStats(vardata);
+ }
+
+ /* without a list of variables, use the expression itself */
+ if (vars == NIL)
+ {
+ VariableStatData vardata;
+
+ /* can we get no vardata for the variable? */
+ examine_variable(root, expr, 0, &vardata);
+
+ exprinfo->varinfos
+ = add_unique_group_var(root, exprinfo->varinfos,
+ expr, &vardata);
+
+ ReleaseVariableStats(vardata);
+ }
+
+ return lappend(exprinfos, exprinfo);
+}
+
+
/*
* estimate_num_groups - Estimate number of groups in a grouped query
*
@@ -3360,7 +3442,7 @@ double
estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
List **pgset)
{
- List *varinfos = NIL;
+ List *exprinfos = NIL;
double srf_multiplier = 1.0;
double numdistinct;
ListCell *l;
@@ -3398,6 +3480,7 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
double this_srf_multiplier;
VariableStatData vardata;
List *varshere;
+ Relids varnos;
ListCell *l2;
/* is expression in this grouping set? */
@@ -3434,8 +3517,9 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
examine_variable(root, groupexpr, 0, &vardata);
if (HeapTupleIsValid(vardata.statsTuple) || vardata.isunique)
{
- varinfos = add_unique_group_var(root, varinfos,
- groupexpr, &vardata);
+ exprinfos = add_unique_group_expr(root, exprinfos,
+ groupexpr, NIL);
+
ReleaseVariableStats(vardata);
continue;
}
@@ -3465,6 +3549,19 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
continue;
}
+ /*
+ * Are all the variables from the same relation? If yes, search for
+ * an extended statistic matching this expression exactly.
+ */
+ varnos = pull_varnos((Node *) varshere);
+ if (bms_membership(varnos) == BMS_SINGLETON)
+ {
+ exprinfos = add_unique_group_expr(root, exprinfos,
+ groupexpr,
+ varshere);
+ continue;
+ }
+
/*
* Else add variables to varinfos list
*/
@@ -3472,9 +3569,8 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
{
Node *var = (Node *) lfirst(l2);
- examine_variable(root, var, 0, &vardata);
- varinfos = add_unique_group_var(root, varinfos, var, &vardata);
- ReleaseVariableStats(vardata);
+ exprinfos = add_unique_group_expr(root, exprinfos,
+ var, NIL);
}
}
@@ -3482,7 +3578,7 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
* If now no Vars, we must have an all-constant or all-boolean GROUP BY
* list.
*/
- if (varinfos == NIL)
+ if (exprinfos == NIL)
{
/* Apply SRF multiplier as we would do in the long path */
numdistinct *= srf_multiplier;
@@ -3506,32 +3602,32 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
*/
do
{
- GroupVarInfo *varinfo1 = (GroupVarInfo *) linitial(varinfos);
- RelOptInfo *rel = varinfo1->rel;
+ GroupExprInfo *exprinfo1 = (GroupExprInfo *) linitial(exprinfos);
+ RelOptInfo *rel = exprinfo1->rel;
double reldistinct = 1;
double relmaxndistinct = reldistinct;
int relvarcount = 0;
- List *newvarinfos = NIL;
- List *relvarinfos = NIL;
+ List *newexprinfos = NIL;
+ List *relexprinfos = NIL;
/*
* Split the list of varinfos in two - one for the current rel, one
* for remaining Vars on other rels.
*/
- relvarinfos = lappend(relvarinfos, varinfo1);
- for_each_from(l, varinfos, 1)
+ relexprinfos = lappend(relexprinfos, exprinfo1);
+ for_each_from(l, exprinfos, 1)
{
- GroupVarInfo *varinfo2 = (GroupVarInfo *) lfirst(l);
+ GroupExprInfo *exprinfo2 = (GroupExprInfo *) lfirst(l);
- if (varinfo2->rel == varinfo1->rel)
+ if (exprinfo2->rel == exprinfo1->rel)
{
/* varinfos on current rel */
- relvarinfos = lappend(relvarinfos, varinfo2);
+ relexprinfos = lappend(relexprinfos, exprinfo2);
}
else
{
- /* not time to process varinfo2 yet */
- newvarinfos = lappend(newvarinfos, varinfo2);
+ /* not time to process exprinfo2 yet */
+ newexprinfos = lappend(newexprinfos, exprinfo2);
}
}
@@ -3547,11 +3643,11 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
* apply. We apply a fudge factor below, but only if we multiplied
* more than one such values.
*/
- while (relvarinfos)
+ while (relexprinfos)
{
double mvndistinct;
- if (estimate_multivariate_ndistinct(root, rel, &relvarinfos,
+ if (estimate_multivariate_ndistinct(root, rel, &relexprinfos,
&mvndistinct))
{
reldistinct *= mvndistinct;
@@ -3561,18 +3657,24 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
}
else
{
- foreach(l, relvarinfos)
+ foreach(l, relexprinfos)
{
- GroupVarInfo *varinfo2 = (GroupVarInfo *) lfirst(l);
+ ListCell *lc;
+ GroupExprInfo *exprinfo2 = (GroupExprInfo *) lfirst(l);
- reldistinct *= varinfo2->ndistinct;
- if (relmaxndistinct < varinfo2->ndistinct)
- relmaxndistinct = varinfo2->ndistinct;
- relvarcount++;
+ foreach (lc, exprinfo2->varinfos)
+ {
+ GroupVarInfo *varinfo2 = (GroupVarInfo *) lfirst(lc);
+
+ reldistinct *= varinfo2->ndistinct;
+ if (relmaxndistinct < varinfo2->ndistinct)
+ relmaxndistinct = varinfo2->ndistinct;
+ relvarcount++;
+ }
}
/* we're done with this relation */
- relvarinfos = NIL;
+ relexprinfos = NIL;
}
}
@@ -3658,8 +3760,8 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
numdistinct *= reldistinct;
}
- varinfos = newvarinfos;
- } while (varinfos != NIL);
+ exprinfos = newexprinfos;
+ } while (exprinfos != NIL);
/* Now we can account for the effects of any SRFs */
numdistinct *= srf_multiplier;
@@ -3877,53 +3979,114 @@ estimate_hashagg_tablesize(PlannerInfo *root, Path *path,
*/
static bool
estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
- List **varinfos, double *ndistinct)
+ List **exprinfos, double *ndistinct)
{
ListCell *lc;
- Bitmapset *attnums = NULL;
- int nmatches;
+ int nmatches_vars;
+ int nmatches_exprs;
Oid statOid = InvalidOid;
MVNDistinct *stats;
- Bitmapset *matched = NULL;
+ StatisticExtInfo *matched_info = NULL;
/* bail out immediately if the table has no extended statistics */
if (!rel->statlist)
return false;
- /* Determine the attnums we're looking for */
- foreach(lc, *varinfos)
- {
- GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc);
- AttrNumber attnum;
-
- Assert(varinfo->rel == rel);
-
- if (!IsA(varinfo->var, Var))
- continue;
-
- attnum = ((Var *) varinfo->var)->varattno;
-
- if (!AttrNumberIsForUserDefinedAttr(attnum))
- continue;
-
- attnums = bms_add_member(attnums, attnum);
- }
-
/* look for the ndistinct statistics matching the most vars */
- nmatches = 1; /* we require at least two matches */
+ nmatches_vars = 0; /* we require at least two matches */
+ nmatches_exprs = 0;
foreach(lc, rel->statlist)
{
+ ListCell *lc2;
StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
- Bitmapset *shared;
- int nshared;
+ int nshared_vars = 0;
+ int nshared_exprs = 0;
/* skip statistics of other kinds */
if (info->kind != STATS_EXT_NDISTINCT)
continue;
- /* compute attnums shared by the vars and the statistics object */
- shared = bms_intersect(info->keys, attnums);
- nshared = bms_num_members(shared);
+ /*
+ * Determine how many expressions (and variables in non-matched
+ * expressions) match. We'll then use these numbers to pick the
+ * statistics object that best matches the clauses.
+ *
+ * XXX There's a bit of trouble with expressions - we search for
+ * an exact match first, and if we don't find a match we try to
+ * search for smaller "partial" expressions extracted from it.
+ * So for example given GROUP BY (a+b) we search for statistics
+ * defined on (a+b) first, and then maybe for one on (a) and (b).
+ * The trouble here is that with the current coding, the one
+ * matching (a) and (b) might win, because we're comparing the
+ * counts. We should probably give some preference to exact
+ * matches of the expressions.
+ */
+ foreach(lc2, *exprinfos)
+ {
+ ListCell *lc3;
+ GroupExprInfo *exprinfo = (GroupExprInfo *) lfirst(lc2);
+ AttrNumber attnum;
+ bool found = false;
+
+ Assert(exprinfo->rel == rel);
+
+ /* simple Var, search in statistics keys directly */
+ if (IsA(exprinfo->expr, Var))
+ {
+ attnum = ((Var *) exprinfo->expr)->varattno;
+
+ if (!AttrNumberIsForUserDefinedAttr(attnum))
+ continue;
+
+ if (bms_is_member(attnum, info->keys))
+ nshared_vars++;
+
+ continue;
+ }
+
+ /* expression - see if it's in the statistics */
+ foreach (lc3, info->exprs)
+ {
+ Node *expr = (Node *) lfirst(lc3);
+
+ if (equal(exprinfo->expr, expr))
+ {
+ nshared_exprs++;
+ found = true;
+ break;
+ }
+ }
+
+ /*
+ * If it's a complex expression, and we have found it in the
+ * statistics object, we're done. Otherwise try to match the
+ * varinfos we've extracted from the expression. That way we
+ * can do at least some estimation.
+ */
+ if (found)
+ continue;
+
+ foreach(lc3, exprinfo->varinfos)
+ {
+ GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc3);
+
+ if (IsA(varinfo->var, Var))
+ {
+ attnum = ((Var *) exprinfo->expr)->varattno;
+
+ if (!AttrNumberIsForUserDefinedAttr(attnum))
+ continue;
+
+ if (bms_is_member(attnum, info->keys))
+ nshared_vars++;
+ }
+
+ /* XXX What if it's not a Var? */
+ }
+ }
+
+ if (nshared_vars + nshared_exprs < 2)
+ continue;
/*
* Does this statistics object match more columns than the currently
@@ -3932,18 +4095,21 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
* XXX This should break ties using name of the object, or something
* like that, to make the outcome stable.
*/
- if (nshared > nmatches)
+ if ((nshared_vars > nmatches_vars) ||
+ ((nshared_vars == nmatches_vars) && (nshared_exprs > nmatches_exprs)))
{
statOid = info->statOid;
- nmatches = nshared;
- matched = shared;
+ nmatches_vars = nshared_vars;
+ nmatches_exprs = nshared_exprs;
+ matched_info = info;
}
}
/* No match? */
if (statOid == InvalidOid)
return false;
- Assert(nmatches > 1 && matched != NULL);
+
+ Assert(nmatches_vars + nmatches_exprs > 1);
stats = statext_ndistinct_load(statOid);
@@ -3956,6 +4122,56 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
int i;
List *newlist = NIL;
MVNDistinctItem *item = NULL;
+ ListCell *lc2;
+ Bitmapset *matched = NULL;
+
+ /* see what actually matched */
+ foreach (lc2, *exprinfos)
+ {
+ ListCell *lc3;
+ int idx;
+ bool found = false;
+
+ GroupExprInfo *exprinfo = (GroupExprInfo *) lfirst(lc2);
+
+ /* expression - see if it's in the statistics */
+ idx = 0;
+ foreach (lc3, matched_info->exprs)
+ {
+ Node *expr = (Node *) lfirst(lc3);
+
+ idx++;
+
+ if (equal(exprinfo->expr, expr))
+ {
+ matched = bms_add_member(matched, MaxHeapAttributeNumber + idx);
+ found = true;
+ break;
+ }
+ }
+
+ if (found)
+ continue;
+
+ foreach (lc3, exprinfo->varinfos)
+ {
+ GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc2);
+
+ /* simple Var, search in statistics keys directly */
+ if (IsA(varinfo->var, Var))
+ {
+ AttrNumber attnum = ((Var *) varinfo->var)->varattno;
+
+ if (!AttrNumberIsForUserDefinedAttr(attnum))
+ continue;
+
+ if (!bms_is_member(attnum, matched_info->keys))
+ continue;
+
+ matched = bms_add_member(matched, attnum);
+ }
+ }
+ }
/* Find the specific item that exactly matches the combination */
for (i = 0; i < stats->nitems; i++)
@@ -3973,28 +4189,49 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
if (!item)
elog(ERROR, "corrupt MVNDistinct entry");
- /* Form the output varinfo list, keeping only unmatched ones */
- foreach(lc, *varinfos)
+ /* Form the output exprinfo list, keeping only unmatched ones */
+ foreach(lc, *exprinfos)
{
- GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc);
+ GroupExprInfo *exprinfo = (GroupExprInfo *) lfirst(lc);
AttrNumber attnum;
+ ListCell *lc3;
+ bool found = false;
+
+ foreach (lc3, matched_info->exprs)
+ {
+ Node *expr = (Node *) lfirst(lc3);
+
+ if (equal(exprinfo->expr, expr))
+ {
+ found = true;
+ break;
+ }
+ }
- if (!IsA(varinfo->var, Var))
+ /* the whole expression was matched, so skip it */
+ if (found)
+ continue;
+
+ if (!IsA(exprinfo->expr, Var))
{
- newlist = lappend(newlist, varinfo);
+ /*
+ * FIXME Probably should remove varinfos that match the
+ * selected MVNDistinct item.
+ */
+ newlist = lappend(newlist, exprinfo);
continue;
}
- attnum = ((Var *) varinfo->var)->varattno;
+ attnum = ((Var *) exprinfo->expr)->varattno;
if (!AttrNumberIsForUserDefinedAttr(attnum))
continue;
if (!bms_is_member(attnum, matched))
- newlist = lappend(newlist, varinfo);
+ newlist = lappend(newlist, exprinfo);
}
- *varinfos = newlist;
+ *exprinfos = newlist;
*ndistinct = item->ndistinct;
return true;
}
@@ -4690,6 +4927,13 @@ get_join_variables(PlannerInfo *root, List *args, SpecialJoinInfo *sjinfo,
*join_is_reversed = false;
}
+/* statext_expressions_load copies the tuple, so just pfree it. */
+static void
+ReleaseDummy(HeapTuple tuple)
+{
+ pfree(tuple);
+}
+
/*
* examine_variable
* Try to look up statistical data about an expression.
@@ -4830,6 +5074,7 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
* operator we are estimating for. FIXME later.
*/
ListCell *ilist;
+ ListCell *slist;
foreach(ilist, onerel->indexlist)
{
@@ -4986,6 +5231,68 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
if (vardata->statsTuple)
break;
}
+
+ /*
+ * Search extended statistics for one with a matching expression.
+ * There might be multiple ones, so just grab the first one. In
+ * the future, we might consider the statistics target (and pick
+ * the most accurate statistics) and maybe some other parameters.
+ */
+ foreach(slist, onerel->statlist)
+ {
+ StatisticExtInfo *info = (StatisticExtInfo *) lfirst(slist);
+ ListCell *expr_item;
+ int pos;
+
+ /*
+ * Stop once we've found statistics for the expression (either
+ * from extended stats, or for an index in the preceding loop).
+ */
+ if (vardata->statsTuple)
+ break;
+
+ /* skip stats without per-expression stats */
+ if (info->kind != STATS_EXT_EXPRESSIONS)
+ continue;
+
+ pos = 0;
+ foreach (expr_item, info->exprs)
+ {
+ Node *expr = (Node *) lfirst(expr_item);
+
+ Assert(expr);
+
+ /* strip RelabelType before comparing it */
+ if (expr && IsA(expr, RelabelType))
+ expr = (Node *) ((RelabelType *) expr)->arg;
+
+ /* found a match, see if we can extract pg_statistic row */
+ if (equal(node, expr))
+ {
+ HeapTuple t = statext_expressions_load(info->statOid, pos);
+
+ vardata->statsTuple = t;
+
+ /*
+ * FIXME not sure if we should cache the tuple somewhere?
+ * It's stored in a cached tuple in the "data" catalog,
+ * and we just create a new copy every time.
+ */
+ vardata->freefunc = ReleaseDummy;
+
+ /*
+ * FIXME Hack to make statistic_proc_security_check happy,
+ * so that this does not get rejected. Probably needs more
+ * thought, just a hack.
+ */
+ vardata->acl_ok = true;
+
+ break;
+ }
+
+ pos++;
+ }
+ }
}
}
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 2b501166b8..23cc23d037 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -2591,6 +2591,18 @@ my %tests = (
unlike => { exclude_dump_test_schema => 1, },
},
+ 'CREATE STATISTICS extended_stats_expression' => {
+ create_order => 99,
+ create_sql => 'CREATE STATISTICS dump_test.test_ext_stats_expr
+ ON (2 * col1) FROM dump_test.test_fifth_table',
+ regexp => qr/^
+ \QCREATE STATISTICS dump_test.test_ext_stats_expr ON ((2 * col1)) FROM dump_test.test_fifth_table;\E
+ /xms,
+ like =>
+ { %full_runs, %dump_test_schema_runs, section_post_data => 1, },
+ unlike => { exclude_dump_test_schema => 1, },
+ },
+
'CREATE SEQUENCE test_table_col1_seq' => {
regexp => qr/^
\QCREATE SEQUENCE dump_test.test_table_col1_seq\E
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 20af5a92b4..c1333b19d6 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2680,15 +2680,16 @@ describeOneTableDetails(const char *schemaname,
/* print any extended statistics */
if (pset.sversion >= 100000)
{
+ /*
+ * FIXME this needs to be version-dependent, because older
+ * versions don't have pg_get_statisticsobjdef_columns.
+ */
printfPQExpBuffer(&buf,
"SELECT oid, "
"stxrelid::pg_catalog.regclass, "
"stxnamespace::pg_catalog.regnamespace AS nsp, "
"stxname,\n"
- " (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(attname),', ')\n"
- " FROM pg_catalog.unnest(stxkeys) s(attnum)\n"
- " JOIN pg_catalog.pg_attribute a ON (stxrelid = a.attrelid AND\n"
- " a.attnum = s.attnum AND NOT attisdropped)) AS columns,\n"
+ "pg_get_statisticsobjdef_columns(oid) AS columns,\n"
" 'd' = any(stxkind) AS ndist_enabled,\n"
" 'f' = any(stxkind) AS deps_enabled,\n"
" 'm' = any(stxkind) AS mcv_enabled,\n");
@@ -2715,33 +2716,60 @@ describeOneTableDetails(const char *schemaname,
for (i = 0; i < tuples; i++)
{
bool gotone = false;
+ bool has_ndistinct;
+ bool has_dependencies;
+ bool has_mcv;
+ bool has_all;
+ bool has_some;
+
+ has_ndistinct = (strcmp(PQgetvalue(result, i, 5), "t") == 0);
+ has_dependencies = (strcmp(PQgetvalue(result, i, 6), "t") == 0);
+ has_mcv = (strcmp(PQgetvalue(result, i, 7), "t") == 0);
printfPQExpBuffer(&buf, " ");
/* statistics object name (qualified with namespace) */
- appendPQExpBuffer(&buf, "\"%s\".\"%s\" (",
+ appendPQExpBuffer(&buf, "\"%s\".\"%s\"",
PQgetvalue(result, i, 2),
PQgetvalue(result, i, 3));
- /* options */
- if (strcmp(PQgetvalue(result, i, 5), "t") == 0)
- {
- appendPQExpBufferStr(&buf, "ndistinct");
- gotone = true;
- }
+ /*
+ * When printing kinds we ignore expression statistics, which
+ * is used only internally and can't be specified by user.
+ * We don't print the kinds when either none are specified
+ * (in which case it has to be statistics on a single expr)
+ * or when all are specified (in which case we assume it's
+ * expanded by CREATE STATISTICS).
+ */
+ has_all = (has_ndistinct && has_dependencies && has_mcv);
+ has_some = (has_ndistinct || has_dependencies || has_mcv);
- if (strcmp(PQgetvalue(result, i, 6), "t") == 0)
+ if (has_some && !has_all)
{
- appendPQExpBuffer(&buf, "%sdependencies", gotone ? ", " : "");
- gotone = true;
- }
+ appendPQExpBuffer(&buf, " (");
- if (strcmp(PQgetvalue(result, i, 7), "t") == 0)
- {
- appendPQExpBuffer(&buf, "%smcv", gotone ? ", " : "");
+ /* options */
+ if (has_ndistinct)
+ {
+ appendPQExpBufferStr(&buf, "ndistinct");
+ gotone = true;
+ }
+
+ if (has_dependencies)
+ {
+ appendPQExpBuffer(&buf, "%sdependencies", gotone ? ", " : "");
+ gotone = true;
+ }
+
+ if (has_mcv)
+ {
+ appendPQExpBuffer(&buf, "%smcv", gotone ? ", " : "");
+ }
+
+ appendPQExpBuffer(&buf, ")");
}
- appendPQExpBuffer(&buf, ") ON %s FROM %s",
+ appendPQExpBuffer(&buf, " ON %s FROM %s",
PQgetvalue(result, i, 4),
PQgetvalue(result, i, 1));
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index b5f52d4e4a..ff33e2f960 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -3652,6 +3652,14 @@
proname => 'pg_get_statisticsobjdef', provolatile => 's',
prorettype => 'text', proargtypes => 'oid',
prosrc => 'pg_get_statisticsobjdef' },
+{ oid => '8887', descr => 'extended statistics columns',
+ proname => 'pg_get_statisticsobjdef_columns', provolatile => 's',
+ prorettype => 'text', proargtypes => 'oid',
+ prosrc => 'pg_get_statisticsobjdef_columns' },
+{ oid => '8886', descr => 'extended statistics expressions',
+ proname => 'pg_get_statisticsobjdef_expressions', provolatile => 's',
+ prorettype => '_text', proargtypes => 'oid',
+ prosrc => 'pg_get_statisticsobjdef_expressions' },
{ oid => '3352', descr => 'partition key description',
proname => 'pg_get_partkeydef', provolatile => 's', prorettype => 'text',
proargtypes => 'oid', prosrc => 'pg_get_partkeydef' },
diff --git a/src/include/catalog/pg_statistic_ext.h b/src/include/catalog/pg_statistic_ext.h
index 99f6cea0a5..cf46a79af9 100644
--- a/src/include/catalog/pg_statistic_ext.h
+++ b/src/include/catalog/pg_statistic_ext.h
@@ -52,6 +52,9 @@ CATALOG(pg_statistic_ext,3381,StatisticExtRelationId)
#ifdef CATALOG_VARLEN
char stxkind[1] BKI_FORCE_NOT_NULL; /* statistics kinds requested
* to build */
+ pg_node_tree stxexprs; /* A list of expression trees for stats
+ * attributes that are not simple column
+ * references. */
#endif
} FormData_pg_statistic_ext;
@@ -77,6 +80,7 @@ DECLARE_INDEX(pg_statistic_ext_relid_index, 3379, on pg_statistic_ext using btre
#define STATS_EXT_NDISTINCT 'd'
#define STATS_EXT_DEPENDENCIES 'f'
#define STATS_EXT_MCV 'm'
+#define STATS_EXT_EXPRESSIONS 'e'
#endif /* EXPOSE_TO_CLIENT_CODE */
diff --git a/src/include/catalog/pg_statistic_ext_data.h b/src/include/catalog/pg_statistic_ext_data.h
index e0aa152f7b..0d2f6a6c32 100644
--- a/src/include/catalog/pg_statistic_ext_data.h
+++ b/src/include/catalog/pg_statistic_ext_data.h
@@ -37,6 +37,7 @@ CATALOG(pg_statistic_ext_data,3429,StatisticExtDataRelationId)
pg_ndistinct stxdndistinct; /* ndistinct coefficients (serialized) */
pg_dependencies stxddependencies; /* dependencies (serialized) */
pg_mcv_list stxdmcv; /* MCV (serialized) */
+ pg_statistic stxdexpr[1]; /* stats for expressions */
#endif
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index caed683ba9..374f047dda 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -451,6 +451,7 @@ typedef enum NodeTag
T_TypeName,
T_ColumnDef,
T_IndexElem,
+ T_StatsElem,
T_Constraint,
T_DefElem,
T_RangeTblEntry,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index dc2bb40926..f2042ba445 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2830,8 +2830,24 @@ typedef struct CreateStatsStmt
List *relations; /* rels to build stats on (list of RangeVar) */
char *stxcomment; /* comment to apply to stats, or NULL */
bool if_not_exists; /* do nothing if stats name already exists */
+ bool transformed; /* true when transformStatsStmt is finished */
} CreateStatsStmt;
+/*
+ * StatsElem - statistics parameters (used in CREATE STATISTICS)
+ *
+ * For a plain attribute, 'name' is the name of the referenced table column
+ * and 'expr' is NULL. For an expression, 'name' is NULL and 'expr' is the
+ * expression tree.
+ */
+typedef struct StatsElem
+{
+ NodeTag type;
+ char *name; /* name of attribute to index, or NULL */
+ Node *expr; /* expression to index, or NULL */
+} StatsElem;
+
+
/* ----------------------
* Alter Statistics Statement
* ----------------------
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index cde2637798..c384f2c6e7 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -915,8 +915,9 @@ typedef struct StatisticExtInfo
Oid statOid; /* OID of the statistics row */
RelOptInfo *rel; /* back-link to statistic's table */
- char kind; /* statistic kind of this entry */
+ char kind; /* statistics kind of this entry */
Bitmapset *keys; /* attnums of the columns covered */
+ List *exprs; /* expressions */
} StatisticExtInfo;
/*
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index dfc214b06f..2b477c38eb 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -69,6 +69,7 @@ typedef enum ParseExprKind
EXPR_KIND_FUNCTION_DEFAULT, /* default parameter value for function */
EXPR_KIND_INDEX_EXPRESSION, /* index expression */
EXPR_KIND_INDEX_PREDICATE, /* index predicate */
+ EXPR_KIND_STATS_EXPRESSION, /* extended statistics expression */
EXPR_KIND_ALTER_COL_TRANSFORM, /* transform expr in ALTER COLUMN TYPE */
EXPR_KIND_EXECUTE_PARAMETER, /* parameter value in EXECUTE */
EXPR_KIND_TRIGGER_WHEN, /* WHEN condition in CREATE TRIGGER */
diff --git a/src/include/parser/parse_utilcmd.h b/src/include/parser/parse_utilcmd.h
index bfa4a6b0f2..1056bf081b 100644
--- a/src/include/parser/parse_utilcmd.h
+++ b/src/include/parser/parse_utilcmd.h
@@ -26,6 +26,8 @@ extern AlterTableStmt *transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
List **afterStmts);
extern IndexStmt *transformIndexStmt(Oid relid, IndexStmt *stmt,
const char *queryString);
+extern CreateStatsStmt *transformStatsStmt(Oid relid, CreateStatsStmt *stmt,
+ const char *queryString);
extern void transformRuleStmt(RuleStmt *stmt, const char *queryString,
List **actions, Node **whereClause);
extern List *transformCreateSchemaStmt(CreateSchemaStmt *stmt);
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index c849bd57c0..092bc3eb8a 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -57,19 +57,35 @@ typedef struct SortItem
int count;
} SortItem;
+/*
+ * Used to pass pre-computed information about expressions the stats
+ * object is defined on.
+ */
+typedef struct ExprInfo
+{
+ int nexprs; /* number of expressions */
+ Oid *collations; /* collation for each expression */
+ Oid *types; /* type of each expression */
+ Datum **values; /* values for each expression */
+ bool **nulls; /* nulls for each expression */
+} ExprInfo;
+
extern MVNDistinct *statext_ndistinct_build(double totalrows,
int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats);
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats);
extern bytea *statext_ndistinct_serialize(MVNDistinct *ndistinct);
extern MVNDistinct *statext_ndistinct_deserialize(bytea *data);
extern MVDependencies *statext_dependencies_build(int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats);
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats);
extern bytea *statext_dependencies_serialize(MVDependencies *dependencies);
extern MVDependencies *statext_dependencies_deserialize(bytea *data);
extern MCVList *statext_mcv_build(int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats,
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats,
double totalrows, int stattarget);
extern bytea *statext_mcv_serialize(MCVList *mcv, VacAttrStats **stats);
extern MCVList *statext_mcv_deserialize(bytea *data);
@@ -93,11 +109,18 @@ extern void *bsearch_arg(const void *key, const void *base,
extern AttrNumber *build_attnums_array(Bitmapset *attrs, int *numattrs);
extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
- TupleDesc tdesc, MultiSortSupport mss,
+ ExprInfo *exprs, TupleDesc tdesc,
+ MultiSortSupport mss,
int numattrs, AttrNumber *attnums);
extern bool examine_clause_args(List *args, Var **varp,
Const **cstp, bool *varonleftp);
+extern bool examine_clause_args2(List *args, Node **exprp,
+ Const **cstp, bool *expronleftp);
+extern bool examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp,
+ bool *varonleftp);
+extern bool examine_opclause_expression2(OpExpr *expr, Node **exprp, Const **cstp,
+ bool *expronleftp);
extern Selectivity mcv_combine_selectivities(Selectivity simple_sel,
Selectivity mcv_sel,
@@ -124,4 +147,13 @@ extern Selectivity mcv_clause_selectivity_or(PlannerInfo *root,
Selectivity *overlap_basesel,
Selectivity *totalsel);
+extern Bitmapset *add_expressions_to_attributes(Bitmapset *attrs, int nexprs);
+
+/* translate 0-based expression index to attnum and back */
+#define EXPRESSION_ATTNUM(index) \
+ (MaxHeapAttributeNumber + (index) + 1)
+
+#define EXPRESSION_INDEX(attnum) \
+ ((attnum) - MaxHeapAttributeNumber - 1)
+
#endif /* EXTENDED_STATS_INTERNAL_H */
diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h
index fec50688ea..006d578e0c 100644
--- a/src/include/statistics/statistics.h
+++ b/src/include/statistics/statistics.h
@@ -121,6 +121,8 @@ extern Selectivity statext_clauselist_selectivity(PlannerInfo *root,
extern bool has_stats_of_kind(List *stats, char requiredkind);
extern StatisticExtInfo *choose_best_statistics(List *stats, char requiredkind,
Bitmapset **clause_attnums,
+ List **clause_exprs,
int nclauses);
+extern HeapTuple statext_expressions_load(Oid stxoid, int idx);
#endif /* STATISTICS_H */
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 10d17be23c..4dc5e6aa5f 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -304,7 +304,9 @@ CREATE TABLE ctlt1 (a text CHECK (length(a) > 2) PRIMARY KEY, b text);
CREATE INDEX ctlt1_b_key ON ctlt1 (b);
CREATE INDEX ctlt1_fnidx ON ctlt1 ((a || b));
CREATE STATISTICS ctlt1_a_b_stat ON a,b FROM ctlt1;
+CREATE STATISTICS ctlt1_expr_stat ON (a || b) FROM ctlt1;
COMMENT ON STATISTICS ctlt1_a_b_stat IS 'ab stats';
+COMMENT ON STATISTICS ctlt1_expr_stat IS 'ab expr stats';
COMMENT ON COLUMN ctlt1.a IS 'A';
COMMENT ON COLUMN ctlt1.b IS 'B';
COMMENT ON CONSTRAINT ctlt1_a_check ON ctlt1 IS 't1_a_check';
@@ -414,7 +416,8 @@ Indexes:
Check constraints:
"ctlt1_a_check" CHECK (length(a) > 2)
Statistics objects:
- "public"."ctlt_all_a_b_stat" (ndistinct, dependencies, mcv) ON a, b FROM ctlt_all
+ "public"."ctlt_all_a_b_stat" ON a, b FROM ctlt_all
+ "public"."ctlt_all_expr_stat" ON ((a || b)) FROM ctlt_all
SELECT c.relname, objsubid, description FROM pg_description, pg_index i, pg_class c WHERE classoid = 'pg_class'::regclass AND objoid = i.indexrelid AND c.oid = i.indexrelid AND i.indrelid = 'ctlt_all'::regclass ORDER BY c.relname, objsubid;
relname | objsubid | description
@@ -424,10 +427,11 @@ SELECT c.relname, objsubid, description FROM pg_description, pg_index i, pg_clas
(2 rows)
SELECT s.stxname, objsubid, description FROM pg_description, pg_statistic_ext s WHERE classoid = 'pg_statistic_ext'::regclass AND objoid = s.oid AND s.stxrelid = 'ctlt_all'::regclass ORDER BY s.stxname, objsubid;
- stxname | objsubid | description
--------------------+----------+-------------
- ctlt_all_a_b_stat | 0 | ab stats
-(1 row)
+ stxname | objsubid | description
+--------------------+----------+---------------
+ ctlt_all_a_b_stat | 0 | ab stats
+ ctlt_all_expr_stat | 0 | ab expr stats
+(2 rows)
CREATE TABLE inh_error1 () INHERITS (ctlt1, ctlt4);
NOTICE: merging multiple inherited definitions of column "a"
@@ -452,7 +456,8 @@ Indexes:
Check constraints:
"ctlt1_a_check" CHECK (length(a) > 2)
Statistics objects:
- "public"."pg_attrdef_a_b_stat" (ndistinct, dependencies, mcv) ON a, b FROM public.pg_attrdef
+ "public"."pg_attrdef_a_b_stat" ON a, b FROM public.pg_attrdef
+ "public"."pg_attrdef_expr_stat" ON ((a || b)) FROM public.pg_attrdef
DROP TABLE public.pg_attrdef;
-- Check that LIKE isn't confused when new table masks the old, either
@@ -473,7 +478,8 @@ Indexes:
Check constraints:
"ctlt1_a_check" CHECK (length(a) > 2)
Statistics objects:
- "ctl_schema"."ctlt1_a_b_stat" (ndistinct, dependencies, mcv) ON a, b FROM ctlt1
+ "ctl_schema"."ctlt1_a_b_stat" ON a, b FROM ctlt1
+ "ctl_schema"."ctlt1_expr_stat" ON ((a || b)) FROM ctlt1
ROLLBACK;
DROP TABLE ctlt1, ctlt2, ctlt3, ctlt4, ctlt12_storage, ctlt12_comments, ctlt1_inh, ctlt13_inh, ctlt13_like, ctlt_all, ctla, ctlb CASCADE;
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 6173473de9..246e151fa0 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2400,6 +2400,7 @@ pg_stats_ext| SELECT cn.nspname AS schemaname,
( SELECT array_agg(a.attname ORDER BY a.attnum) AS array_agg
FROM (unnest(s.stxkeys) k(k)
JOIN pg_attribute a ON (((a.attrelid = s.stxrelid) AND (a.attnum = k.k))))) AS attnames,
+ pg_get_statisticsobjdef_expressions(s.oid) AS exprs,
s.stxkind AS kinds,
sd.stxdndistinct AS n_distinct,
sd.stxddependencies AS dependencies,
@@ -2421,6 +2422,80 @@ pg_stats_ext| SELECT cn.nspname AS schemaname,
FROM (unnest(s.stxkeys) k(k)
JOIN pg_attribute a ON (((a.attrelid = s.stxrelid) AND (a.attnum = k.k))))
WHERE (NOT has_column_privilege(c.oid, a.attnum, 'select'::text))))) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_stats_ext_exprs| SELECT cn.nspname AS schemaname,
+ c.relname AS tablename,
+ sn.nspname AS statistics_schemaname,
+ s.stxname AS statistics_name,
+ pg_get_userbyid(s.stxowner) AS statistics_owner,
+ stat.expr,
+ (stat.a).stanullfrac AS null_frac,
+ (stat.a).stawidth AS avg_width,
+ (stat.a).stadistinct AS n_distinct,
+ CASE
+ WHEN ((stat.a).stakind1 = 1) THEN (stat.a).stavalues1
+ WHEN ((stat.a).stakind2 = 1) THEN (stat.a).stavalues2
+ WHEN ((stat.a).stakind3 = 1) THEN (stat.a).stavalues3
+ WHEN ((stat.a).stakind4 = 1) THEN (stat.a).stavalues4
+ WHEN ((stat.a).stakind5 = 1) THEN (stat.a).stavalues5
+ ELSE NULL::anyarray
+ END AS most_common_vals,
+ CASE
+ WHEN ((stat.a).stakind1 = 1) THEN (stat.a).stanumbers1
+ WHEN ((stat.a).stakind2 = 1) THEN (stat.a).stanumbers2
+ WHEN ((stat.a).stakind3 = 1) THEN (stat.a).stanumbers3
+ WHEN ((stat.a).stakind4 = 1) THEN (stat.a).stanumbers4
+ WHEN ((stat.a).stakind5 = 1) THEN (stat.a).stanumbers5
+ ELSE NULL::real[]
+ END AS most_common_freqs,
+ CASE
+ WHEN ((stat.a).stakind1 = 2) THEN (stat.a).stavalues1
+ WHEN ((stat.a).stakind2 = 2) THEN (stat.a).stavalues2
+ WHEN ((stat.a).stakind3 = 2) THEN (stat.a).stavalues3
+ WHEN ((stat.a).stakind4 = 2) THEN (stat.a).stavalues4
+ WHEN ((stat.a).stakind5 = 2) THEN (stat.a).stavalues5
+ ELSE NULL::anyarray
+ END AS histogram_bounds,
+ CASE
+ WHEN ((stat.a).stakind1 = 3) THEN (stat.a).stanumbers1[1]
+ WHEN ((stat.a).stakind2 = 3) THEN (stat.a).stanumbers2[1]
+ WHEN ((stat.a).stakind3 = 3) THEN (stat.a).stanumbers3[1]
+ WHEN ((stat.a).stakind4 = 3) THEN (stat.a).stanumbers4[1]
+ WHEN ((stat.a).stakind5 = 3) THEN (stat.a).stanumbers5[1]
+ ELSE NULL::real
+ END AS correlation,
+ CASE
+ WHEN ((stat.a).stakind1 = 4) THEN (stat.a).stavalues1
+ WHEN ((stat.a).stakind2 = 4) THEN (stat.a).stavalues2
+ WHEN ((stat.a).stakind3 = 4) THEN (stat.a).stavalues3
+ WHEN ((stat.a).stakind4 = 4) THEN (stat.a).stavalues4
+ WHEN ((stat.a).stakind5 = 4) THEN (stat.a).stavalues5
+ ELSE NULL::anyarray
+ END AS most_common_elems,
+ CASE
+ WHEN ((stat.a).stakind1 = 4) THEN (stat.a).stanumbers1
+ WHEN ((stat.a).stakind2 = 4) THEN (stat.a).stanumbers2
+ WHEN ((stat.a).stakind3 = 4) THEN (stat.a).stanumbers3
+ WHEN ((stat.a).stakind4 = 4) THEN (stat.a).stanumbers4
+ WHEN ((stat.a).stakind5 = 4) THEN (stat.a).stanumbers5
+ ELSE NULL::real[]
+ END AS most_common_elem_freqs,
+ CASE
+ WHEN ((stat.a).stakind1 = 5) THEN (stat.a).stanumbers1
+ WHEN ((stat.a).stakind2 = 5) THEN (stat.a).stanumbers2
+ WHEN ((stat.a).stakind3 = 5) THEN (stat.a).stanumbers3
+ WHEN ((stat.a).stakind4 = 5) THEN (stat.a).stanumbers4
+ WHEN ((stat.a).stakind5 = 5) THEN (stat.a).stanumbers5
+ ELSE NULL::real[]
+ END AS elem_count_histogram
+ FROM (((((pg_statistic_ext s
+ JOIN pg_class c ON ((c.oid = s.stxrelid)))
+ JOIN pg_statistic_ext_data sd ON ((s.oid = sd.stxoid)))
+ LEFT JOIN pg_namespace cn ON ((cn.oid = c.relnamespace)))
+ LEFT JOIN pg_namespace sn ON ((sn.oid = s.stxnamespace)))
+ LEFT JOIN LATERAL ( SELECT x.expr,
+ x.a
+ FROM ( SELECT unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr,
+ unnest(sd.stxdexpr) AS a) x) stat ON ((sd.stxdexpr IS NOT NULL)));
pg_tables| SELECT n.nspname AS schemaname,
c.relname AS tablename,
pg_get_userbyid(c.relowner) AS tableowner,
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 431b3fa3de..36b7e3e7d3 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -25,7 +25,7 @@ begin
end;
$$;
-- Verify failures
-CREATE TABLE ext_stats_test (x int, y int, z int);
+CREATE TABLE ext_stats_test (x text, y int, z int);
CREATE STATISTICS tst;
ERROR: syntax error at or near ";"
LINE 1: CREATE STATISTICS tst;
@@ -44,12 +44,25 @@ CREATE STATISTICS tst ON a, b FROM ext_stats_test;
ERROR: column "a" does not exist
CREATE STATISTICS tst ON x, x, y FROM ext_stats_test;
ERROR: duplicate column name in statistics definition
-CREATE STATISTICS tst ON x + y FROM ext_stats_test;
-ERROR: only simple column references are allowed in CREATE STATISTICS
-CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
-ERROR: only simple column references are allowed in CREATE STATISTICS
+CREATE STATISTICS tst ON x, x, y, x, x, y, x, x, y FROM ext_stats_test;
+ERROR: cannot have more than 8 columns in statistics
+CREATE STATISTICS tst ON x, x, y, x, x, (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+ERROR: cannot have more than 8 columns in statistics
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+ERROR: cannot have more than 8 columns in statistics
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), y FROM ext_stats_test;
+ERROR: duplicate expression in statistics definition
CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
ERROR: unrecognized statistics kind "unrecognized"
+-- incorrect expressions
+CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
+ERROR: syntax error at or near "+"
+LINE 1: CREATE STATISTICS tst ON y + z FROM ext_stats_test;
+ ^
+CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
+ERROR: syntax error at or near ","
+LINE 1: CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
+ ^
DROP TABLE ext_stats_test;
-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
@@ -79,7 +92,7 @@ ALTER TABLE ab1 DROP COLUMN a;
b | integer | | |
c | integer | | |
Statistics objects:
- "public"."ab1_b_c_stats" (ndistinct, dependencies, mcv) ON b, c FROM ab1
+ "public"."ab1_b_c_stats" ON b, c FROM ab1
-- Ensure statistics are dropped when table is
SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
@@ -111,7 +124,7 @@ ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
a | integer | | |
b | integer | | |
Statistics objects:
- "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1; STATISTICS 0
+ "public"."ab1_a_b_stats" ON a, b FROM ab1; STATISTICS 0
ANALYZE ab1;
SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
@@ -131,7 +144,7 @@ ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
a | integer | | | | plain | |
b | integer | | | | plain | |
Statistics objects:
- "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1
+ "public"."ab1_a_b_stats" ON a, b FROM ab1
-- partial analyze doesn't build stats either
ANALYZE ab1 (a);
@@ -150,6 +163,39 @@ CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
ANALYZE ab1;
DROP TABLE ab1 CASCADE;
NOTICE: drop cascades to table ab1c
+-- basic test for statistics on expressions
+CREATE TABLE ab1 (a INTEGER, b INTEGER, c TIMESTAMP, d TIMESTAMPTZ);
+-- expression stats may be built on a single expression column
+CREATE STATISTICS ab1_exprstat_1 ON (a+b) FROM ab1;
+-- with a single expression, we only enable expression statistics
+CREATE STATISTICS ab1_exprstat_2 ON (a+b) FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_2';
+ stxkind
+---------
+ {e}
+(1 row)
+
+-- adding anything to the expression builds all statistics kinds
+CREATE STATISTICS ab1_exprstat_3 ON (a+b), a FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_3';
+ stxkind
+-----------
+ {d,f,m,e}
+(1 row)
+
+-- date_trunc on timestamptz is not immutable, but that should not matter
+CREATE STATISTICS ab1_exprstat_4 ON date_trunc('day', d) FROM ab1;
+-- date_trunc on timestamp is immutable
+CREATE STATISTICS ab1_exprstat_5 ON date_trunc('day', c) FROM ab1;
+-- insert some data and run analyze, to test that these cases build properly
+INSERT INTO ab1
+SELECT
+ generate_series(1,10),
+ generate_series(1,10),
+ generate_series('2020-10-01'::timestamp, '2020-10-10'::timestamp, interval '1 day'),
+ generate_series('2020-10-01'::timestamptz, '2020-10-10'::timestamptz, interval '1 day');
+ANALYZE ab1;
+DROP TABLE ab1;
-- Verify supported object types for extended statistics
CREATE schema tststats;
CREATE TABLE tststats.t (a int, b int, c text);
@@ -427,6 +473,40 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
1 | 1
(1 row)
+-- a => b, a => c, b => c
+TRUNCATE functional_dependencies;
+DROP STATISTICS func_deps_stat;
+-- now do the same thing, but with expressions
+INSERT INTO functional_dependencies (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+ANALYZE functional_dependencies;
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 35
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 5
+(1 row)
+
+-- create statistics
+CREATE STATISTICS func_deps_stat (dependencies) ON (mod(a,11)), (mod(b::int, 13)), (mod(c, 7)) FROM functional_dependencies;
+ANALYZE functional_dependencies;
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+ estimated | actual
+-----------+--------
+ 35 | 35
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+ estimated | actual
+-----------+--------
+ 5 | 5
+(1 row)
+
-- a => b, a => c, b => c
TRUNCATE functional_dependencies;
DROP STATISTICS func_deps_stat;
@@ -896,6 +976,39 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
1 | 1
(1 row)
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+-- random data (no MCV list), but with expression
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 4
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 1
+(1 row)
+
+-- create statistics
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,37)), (mod(b::int,41)), (mod(c,47)) FROM mcv_lists;
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+ estimated | actual
+-----------+--------
+ 3 | 4
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 1
+(1 row)
+
-- 100 distinct combinations, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -1121,6 +1234,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
200 | 200
(1 row)
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
estimated | actual
-----------+--------
@@ -1207,6 +1326,458 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
50 | 50
(1 row)
+-- 100 distinct combinations, all in the MCV list, but with expressions
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+ANALYZE mcv_lists;
+-- without any stats on the expressions, we have to use default selectivities, which
+-- is why the estimates here are different from the pre-computed case above
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 75 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 75 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+ estimated | actual
+-----------+--------
+ 53 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+ estimated | actual
+-----------+--------
+ 53 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 391 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+ estimated | actual
+-----------+--------
+ 391 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 6 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+ estimated | actual
+-----------+--------
+ 6 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 75 | 200
+(1 row)
+
+-- create statistics with expressions only (we create three separate stats, in order not to build more complex extended stats)
+CREATE STATISTICS mcv_lists_stats_1 ON (mod(a,100)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_2 ON (mod(b::int,50)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_3 ON (mod(c,25)) FROM mcv_lists;
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 343 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 343 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+ estimated | actual
+-----------+--------
+ 26 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+ estimated | actual
+-----------+--------
+ 26 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 10 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+ estimated | actual
+-----------+--------
+ 10 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 1 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+ estimated | actual
+-----------+--------
+ 1 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 343 | 200
+(1 row)
+
+DROP STATISTICS mcv_lists_stats_1;
+DROP STATISTICS mcv_lists_stats_2;
+DROP STATISTICS mcv_lists_stats_3;
+-- create statistics with both MCV and expressions
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,100)), (mod(b::int,50)), (mod(c,25)) FROM mcv_lists;
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+ estimated | actual
+-----------+--------
+ 150 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+ estimated | actual
+-----------+--------
+ 150 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+-- we can't use the statistic for OR clauses that are not fully covered (missing 'd' attribute)
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
-- 100 distinct combinations with NULL values, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -1712,6 +2283,100 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
(1 row)
DROP TABLE mcv_lists_multi;
+-- statistics on integer expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+CREATE STATISTICS expr_stats_1 (mcv) ON (a+b), (a-b), (2*a), (3*b) FROM expr_stats;
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+DROP STATISTICS expr_stats_1;
+DROP TABLE expr_stats;
+-- statistics on a mix columns and expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 0
+(1 row)
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (2*a), (3*b), (a+b), (a-b) FROM expr_stats;
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 0
+(1 row)
+
+DROP TABLE expr_stats;
+-- statistics on expressions with different data types
+CREATE TABLE expr_stats (a int, b name, c text);
+INSERT INTO expr_stats SELECT mod(i,10), md5(mod(i,10)::text), md5(mod(i,10)::text) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+ estimated | actual
+-----------+--------
+ 111 | 1000
+(1 row)
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (b || c), (c || b) FROM expr_stats;
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+DROP TABLE expr_stats;
-- Permission tests. Users should not be able to see specific data values in
-- the extended statistics, if they lack permission to see those values in
-- the underlying table.
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 06b76f949d..4929d373a2 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -124,7 +124,9 @@ CREATE TABLE ctlt1 (a text CHECK (length(a) > 2) PRIMARY KEY, b text);
CREATE INDEX ctlt1_b_key ON ctlt1 (b);
CREATE INDEX ctlt1_fnidx ON ctlt1 ((a || b));
CREATE STATISTICS ctlt1_a_b_stat ON a,b FROM ctlt1;
+CREATE STATISTICS ctlt1_expr_stat ON (a || b) FROM ctlt1;
COMMENT ON STATISTICS ctlt1_a_b_stat IS 'ab stats';
+COMMENT ON STATISTICS ctlt1_expr_stat IS 'ab expr stats';
COMMENT ON COLUMN ctlt1.a IS 'A';
COMMENT ON COLUMN ctlt1.b IS 'B';
COMMENT ON CONSTRAINT ctlt1_a_check ON ctlt1 IS 't1_a_check';
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 0d7a114b19..bd2ada1676 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -28,16 +28,21 @@ end;
$$;
-- Verify failures
-CREATE TABLE ext_stats_test (x int, y int, z int);
+CREATE TABLE ext_stats_test (x text, y int, z int);
CREATE STATISTICS tst;
CREATE STATISTICS tst ON a, b;
CREATE STATISTICS tst FROM sometab;
CREATE STATISTICS tst ON a, b FROM nonexistent;
CREATE STATISTICS tst ON a, b FROM ext_stats_test;
CREATE STATISTICS tst ON x, x, y FROM ext_stats_test;
-CREATE STATISTICS tst ON x + y FROM ext_stats_test;
-CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
+CREATE STATISTICS tst ON x, x, y, x, x, y, x, x, y FROM ext_stats_test;
+CREATE STATISTICS tst ON x, x, y, x, x, (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), y FROM ext_stats_test;
CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
+-- incorrect expressions
+CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
+CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
DROP TABLE ext_stats_test;
-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
@@ -97,6 +102,36 @@ CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
ANALYZE ab1;
DROP TABLE ab1 CASCADE;
+-- basic test for statistics on expressions
+CREATE TABLE ab1 (a INTEGER, b INTEGER, c TIMESTAMP, d TIMESTAMPTZ);
+
+-- expression stats may be built on a single expression column
+CREATE STATISTICS ab1_exprstat_1 ON (a+b) FROM ab1;
+
+-- with a single expression, we only enable expression statistics
+CREATE STATISTICS ab1_exprstat_2 ON (a+b) FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_2';
+
+-- adding anything to the expression builds all statistics kinds
+CREATE STATISTICS ab1_exprstat_3 ON (a+b), a FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_3';
+
+-- date_trunc on timestamptz is not immutable, but that should not matter
+CREATE STATISTICS ab1_exprstat_4 ON date_trunc('day', d) FROM ab1;
+
+-- date_trunc on timestamp is immutable
+CREATE STATISTICS ab1_exprstat_5 ON date_trunc('day', c) FROM ab1;
+
+-- insert some data and run analyze, to test that these cases build properly
+INSERT INTO ab1
+SELECT
+ generate_series(1,10),
+ generate_series(1,10),
+ generate_series('2020-10-01'::timestamp, '2020-10-10'::timestamp, interval '1 day'),
+ generate_series('2020-10-01'::timestamptz, '2020-10-10'::timestamptz, interval '1 day');
+ANALYZE ab1;
+DROP TABLE ab1;
+
-- Verify supported object types for extended statistics
CREATE schema tststats;
@@ -272,6 +307,29 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
TRUNCATE functional_dependencies;
DROP STATISTICS func_deps_stat;
+-- now do the same thing, but with expressions
+INSERT INTO functional_dependencies (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+
+ANALYZE functional_dependencies;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+
+-- create statistics
+CREATE STATISTICS func_deps_stat (dependencies) ON (mod(a,11)), (mod(b::int, 13)), (mod(c, 7)) FROM functional_dependencies;
+
+ANALYZE functional_dependencies;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+
+-- a => b, a => c, b => c
+TRUNCATE functional_dependencies;
+DROP STATISTICS func_deps_stat;
+
INSERT INTO functional_dependencies (a, b, c, filler1)
SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i);
@@ -479,6 +537,28 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'' AND c = 1');
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+
+-- random data (no MCV list), but with expression
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+
+-- create statistics
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,37)), (mod(b::int,41)), (mod(c,47)) FROM mcv_lists;
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+
-- 100 distinct combinations, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -565,6 +645,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
+
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52, NULL) AND b IN ( ''1'', ''2'', NULL)');
@@ -602,6 +684,180 @@ ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
+
+-- 100 distinct combinations, all in the MCV list, but with expressions
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+
+ANALYZE mcv_lists;
+
+-- without any stats on the expressions, we have to use default selectivities, which
+-- is why the estimates here are different from the pre-computed case above
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+-- create statistics with expressions only (we create three separate stats, in order not to build more complex extended stats)
+CREATE STATISTICS mcv_lists_stats_1 ON (mod(a,100)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_2 ON (mod(b::int,50)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_3 ON (mod(c,25)) FROM mcv_lists;
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+DROP STATISTICS mcv_lists_stats_1;
+DROP STATISTICS mcv_lists_stats_2;
+DROP STATISTICS mcv_lists_stats_3;
+
+-- create statistics with both MCV and expressions
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,100)), (mod(b::int,50)), (mod(c,25)) FROM mcv_lists;
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+
+-- we can't use the statistic for OR clauses that are not fully covered (missing 'd' attribute)
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
-- 100 distinct combinations with NULL values, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -894,6 +1150,57 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
DROP TABLE mcv_lists_multi;
+
+-- statistics on integer expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+
+CREATE STATISTICS expr_stats_1 (mcv) ON (a+b), (a-b), (2*a), (3*b) FROM expr_stats;
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+
+DROP STATISTICS expr_stats_1;
+DROP TABLE expr_stats;
+
+-- statistics on a mix columns and expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (2*a), (3*b), (a+b), (a-b) FROM expr_stats;
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+
+DROP TABLE expr_stats;
+
+-- statistics on expressions with different data types
+CREATE TABLE expr_stats (a int, b name, c text);
+INSERT INTO expr_stats SELECT mod(i,10), md5(mod(i,10)::text), md5(mod(i,10)::text) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (b || c), (c || b) FROM expr_stats;
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+
+DROP TABLE expr_stats;
+
+
-- Permission tests. Users should not be able to see specific data values in
-- the extended statistics, if they lack permission to see those values in
-- the underlying table.
--
2.26.2
--------------1F4A19FEB5D90C72707AFA7B--
^ permalink raw reply [nested|flat] 4+ messages in thread
* Handle infinite recursion in logical replication setup
@ 2022-02-23 06:29 vignesh C <[email protected]>
2022-04-05 02:47 ` Re: Handle infinite recursion in logical replication setup Peter Smith <[email protected]>
0 siblings, 1 reply; 4+ messages in thread
From: vignesh C @ 2022-02-23 06:29 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>
Hi,
In logical replication, currently Walsender sends the data that is
generated locally and the data that are replicated from other
instances. This results in infinite recursion in circular logical
replication setup.
Here the user is trying to have a 2-way replication setup with node 1
publishing data to node2 and node2 publishing data to node1, so that
the user can perform dml operations from any node, it can act as a
2-way multi master replication setup.
This problem can be reproduced with the following steps:
-- Instance 1
create publication pub1 for table t1;
create table t1(c1 int);
-- Instance 2
create table t1(c1 int);
create publication pub2 for table t1;
create subscription sub1 CONNECTION 'dbname=postgres port=5432'
publication pub1;
-- Instance 1
create subscription sub2 CONNECTION 'dbname=postgres port=5433'
publication pub2; insert into t1 values(10);
In this scenario, the Walsender in publisher pub1 sends data to the
apply worker in subscriber sub1, the apply worker in sub1 maps the
data to local tables and applies the individual changes as they are
received. Then the Walsender in publisher pub2 sends data to the apply
worker in subscriber sub2, the apply worker in sub2 maps the data to
local tables and applies the individual changes as they are received.
This process repeats infinitely.
Currently we do not differentiate if the data is locally generated
data, or a replicated data and we send both the data which causes
infinite recursion.
We could see that the record count has increased significantly within sometime:
select count(*) from t1;
count
--------------
4000000
(1 row)
If the table had primary key constraint, we could notice that the
first insert is successful and when the same insert is sent back, the
insert fails because of constraint error:
2022-02-23 09:28:43.592 IST [14743] ERROR: duplicate key value
violates unique constraint "t1_pkey"
2022-02-23 09:28:43.592 IST [14743] DETAIL: Key (c1)=(10) already exists.
2022-02-23 09:28:43.592 IST [14743] CONTEXT: processing remote data
during "INSERT" for replication target relation "public.t1" in
transaction 727 at 2022-02-23 09:28:43.406738+05:30
2022-02-23 09:28:43.593 IST [14678] LOG: background worker "logical
replication worker" (PID 14743) exited with exit code 1
2022-02-23 09:28:48.608 IST [14745] LOG: logical replication apply
worker for subscription "sub2" has started
2022-02-23 09:28:48.624 IST [14745] ERROR: duplicate key value
violates unique constraint "t1_pkey"
2022-02-23 09:28:48.624 IST [14745] DETAIL: Key (c1)=(10) already exists.
2022-02-23 09:28:48.624 IST [14745] CONTEXT: processing remote data
during "INSERT" for replication target relation "public.t1" in
transaction 727 at 2022-02-23 09:28:43.406738+05:30
2022-02-23 09:28:48.626 IST [14678] LOG: background worker "logical
replication worker" (PID 14745) exited with exit code 1
The same problem can occur in any circular node setup like 3 nodes,
4node etc like: a) node1 publishing to node2 b) node2 publishing to
node3 c) node3 publishing back to node1.
Here there are two problems for the user: a) incremental
synchronization of table sending both local data and replicated data
by walsender b) Table synchronization of table using copy command
sending both local data and replicated data
For the first problem "Incremental synchronization of table by
Walsender" can be solved by:
Currently the locally generated data does not have replication origin
associated and the data that has originated from another instance will
have a replication origin associated. We could use this information to
differentiate locally generated data and replicated data and send only
the locally generated data. This "only_local" could be provided as an
option while subscription is created:
ex: CREATE SUBSCRIPTION sub1 CONNECTION 'dbname =postgres port=5433'
PUBLICATION pub1 with (only_local = on);
I have attached a basic patch for this, if the idea is accepted, I
will work further to test more scenarios, add documentation, and test
and post an updated patch.
For the second problem, Table synchronization of table including local
data and replicated data using copy command.
Let us consider the following scenario:
a) node1 publishing to node2 b) node2 publishing to node1. Here in
this case node1 will have replicated data from node2 and vice versa.
In the above if user wants to include node3 to subscribe data from
node2. Users will have to create a subscription in node3 to get the
data from node2. During table synchronization we send the complete
table data from node2 to node3. Node2 will have local data from node2
and also replicated data from node1. Currently we don't have an option
to differentiate between the locally generated data and replicated
data in the heap which will cause infinite recursion as described
above.
To handle this if user has specified only_local option, we could throw
a warning or error out while creating subscription in this case, we
could have a column srreplicateddata in pg_subscription_rel which
could indicate if the table has any replicated data or not:
postgres=# select * from pg_subscription_rel;
srsubid | srrelid | srsubstate | srsublsn | srreplicateddata
---------+---------+------------+-----------+------------------
16389 | 16384 | r | 0/14A4640 | t
16389 | 16385 | r | 0/14A4690 | f
(1 row)
In the above example, srreplicateddata with true indicates, tabel t1
whose relid is 16384 has replicated data and the other row having
srreplicateddata as false indicates table t2 whose relid is 16385
does not have replicated data.
When creating a new subscription, the subscriber will connect to the
publisher and check if the relation has replicated data by checking
srreplicateddata in pg_subscription_rel table.
If the table has any replicated data, log a warning or error for this.
Also, we could document the steps on how to handle the initial sync like:
a) Complete the ongoing transactions on this table in the replication
setup nodes i.e. node1 and node2 in the above case, so that the table
data is consistent, b) Once there are no ongoing transaction, Copy the
table data using copy command from any one of the nodes, c) create
subscription with copy_data option as off d) Perform further
transactions on the table e) All the further transactions performed
will be handled by the walsender which will take care of skipping
replicated data and sending only the local data. i.e. node2 will send
the locally generated data to node3.
I'm not sure if there is any other better way to handle this. If there
is a better way, we could handle it accordingly.
Thoughts?
Regards,
Vignesh
Attachments:
[application/x-patch] v1-0001-Skip-replication-of-non-local-data.patch (33.7K, ../../CALDaNm0gwjY_4HFxvvty01BOT01q_fJLKQ3pWP9=9orqubhjcQ@mail.gmail.com/2-v1-0001-Skip-replication-of-non-local-data.patch)
download | inline diff:
From f7bc51504919a5f34265a0f02720f1b0b34fc480 Mon Sep 17 00:00:00 2001
From: Vigneshwaran C <[email protected]>
Date: Wed, 23 Feb 2022 11:37:30 +0530
Subject: [PATCH v1] Skip replication of non local data.
Add an option only_local which will subscribe only to the locally
generated data in the publisher node. If subscriber is created with this
option, publisher will skip publishing the data that was subscribed
from other nodes. It can be created using following syntax:
ex: CREATE SUBSCRIPTION sub1 CONNECTION 'dbname =postgres port=9999' PUBLICATION pub1 with (only_local = on);
---
contrib/test_decoding/test_decoding.c | 13 +++++++
src/backend/catalog/pg_subscription.c | 1 +
src/backend/catalog/system_views.sql | 3 +-
src/backend/commands/subscriptioncmds.c | 20 +++++++++--
.../libpqwalreceiver/libpqwalreceiver.c | 18 ++++++++--
src/backend/replication/logical/decode.c | 36 ++++++++++++++-----
src/backend/replication/logical/logical.c | 35 ++++++++++++++++++
src/backend/replication/logical/tablesync.c | 2 +-
src/backend/replication/logical/worker.c | 1 +
src/backend/replication/pgoutput/pgoutput.c | 25 +++++++++++++
src/backend/replication/slot.c | 4 ++-
src/backend/replication/slotfuncs.c | 18 +++++++---
src/backend/replication/walreceiver.c | 2 +-
src/backend/replication/walsender.c | 21 ++++++++---
src/bin/psql/tab-complete.c | 2 +-
src/include/catalog/pg_proc.dat | 6 ++--
src/include/catalog/pg_subscription.h | 3 ++
src/include/replication/logical.h | 4 +++
src/include/replication/output_plugin.h | 7 ++++
src/include/replication/pgoutput.h | 1 +
src/include/replication/slot.h | 5 ++-
src/include/replication/walreceiver.h | 8 +++--
src/test/regress/expected/rules.out | 5 +--
src/tools/pgindent/typedefs.list | 1 +
24 files changed, 205 insertions(+), 36 deletions(-)
diff --git a/contrib/test_decoding/test_decoding.c b/contrib/test_decoding/test_decoding.c
index ea22649e41..58bc5dbc1c 100644
--- a/contrib/test_decoding/test_decoding.c
+++ b/contrib/test_decoding/test_decoding.c
@@ -73,6 +73,8 @@ static void pg_decode_truncate(LogicalDecodingContext *ctx,
ReorderBufferChange *change);
static bool pg_decode_filter(LogicalDecodingContext *ctx,
RepOriginId origin_id);
+static bool pg_decode_filter_remotedata(LogicalDecodingContext *ctx,
+ RepOriginId origin_id);
static void pg_decode_message(LogicalDecodingContext *ctx,
ReorderBufferTXN *txn, XLogRecPtr message_lsn,
bool transactional, const char *prefix,
@@ -148,6 +150,7 @@ _PG_output_plugin_init(OutputPluginCallbacks *cb)
cb->truncate_cb = pg_decode_truncate;
cb->commit_cb = pg_decode_commit_txn;
cb->filter_by_origin_cb = pg_decode_filter;
+ cb->filter_remotedata_cb = pg_decode_filter_remotedata;
cb->shutdown_cb = pg_decode_shutdown;
cb->message_cb = pg_decode_message;
cb->sequence_cb = pg_decode_sequence;
@@ -484,6 +487,16 @@ pg_decode_filter(LogicalDecodingContext *ctx,
return false;
}
+static bool
+pg_decode_filter_remotedata(LogicalDecodingContext *ctx,
+ RepOriginId origin_id)
+{
+ TestDecodingData *data = ctx->output_plugin_private;
+
+ if (data->only_local && origin_id != InvalidRepOriginId)
+ return true;
+ return false;
+}
/*
* Print literal `outputstr' already represented as string of type `typid'
* into stringbuf `s'.
diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index ca65a8bd20..94e096e5fb 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -69,6 +69,7 @@ GetSubscription(Oid subid, bool missing_ok)
sub->binary = subform->subbinary;
sub->stream = subform->substream;
sub->twophasestate = subform->subtwophasestate;
+ sub->onlylocaldata = subform->subonlylocaldata;
/* Get conninfo */
datum = SysCacheGetAttr(SUBSCRIPTIONOID,
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 3cb69b1f87..931c549f7c 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -958,7 +958,8 @@ CREATE VIEW pg_replication_slots AS
L.confirmed_flush_lsn,
L.wal_status,
L.safe_wal_size,
- L.two_phase
+ L.two_phase,
+ L.only_local
FROM pg_get_replication_slots() AS L
LEFT JOIN pg_database D ON (L.datoid = D.oid);
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 3ef6607d24..3f5cbe2c20 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -61,6 +61,7 @@
#define SUBOPT_BINARY 0x00000080
#define SUBOPT_STREAMING 0x00000100
#define SUBOPT_TWOPHASE_COMMIT 0x00000200
+#define SUBOPT_ONLYLOCAL_DATA 0x00000400
/* check if the 'val' has 'bits' set */
#define IsSet(val, bits) (((val) & (bits)) == (bits))
@@ -82,6 +83,7 @@ typedef struct SubOpts
bool binary;
bool streaming;
bool twophase;
+ bool onlylocal_data;
} SubOpts;
static List *fetch_table_list(WalReceiverConn *wrconn, List *publications);
@@ -130,6 +132,8 @@ parse_subscription_options(ParseState *pstate, List *stmt_options,
opts->streaming = false;
if (IsSet(supported_opts, SUBOPT_TWOPHASE_COMMIT))
opts->twophase = false;
+ if (IsSet(supported_opts, SUBOPT_ONLYLOCAL_DATA))
+ opts->onlylocal_data = false;
/* Parse options */
foreach(lc, stmt_options)
@@ -228,6 +232,15 @@ parse_subscription_options(ParseState *pstate, List *stmt_options,
opts->specified_opts |= SUBOPT_STREAMING;
opts->streaming = defGetBoolean(defel);
}
+ else if (IsSet(supported_opts, SUBOPT_ONLYLOCAL_DATA) &&
+ strcmp(defel->defname, "only_local") == 0)
+ {
+ if (IsSet(opts->specified_opts, SUBOPT_ONLYLOCAL_DATA))
+ errorConflictingDefElem(defel, pstate);
+
+ opts->specified_opts |= SUBOPT_ONLYLOCAL_DATA;
+ opts->onlylocal_data = defGetBoolean(defel);
+ }
else if (strcmp(defel->defname, "two_phase") == 0)
{
/*
@@ -390,7 +403,8 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
supported_opts = (SUBOPT_CONNECT | SUBOPT_ENABLED | SUBOPT_CREATE_SLOT |
SUBOPT_SLOT_NAME | SUBOPT_COPY_DATA |
SUBOPT_SYNCHRONOUS_COMMIT | SUBOPT_BINARY |
- SUBOPT_STREAMING | SUBOPT_TWOPHASE_COMMIT);
+ SUBOPT_STREAMING | SUBOPT_TWOPHASE_COMMIT |
+ SUBOPT_ONLYLOCAL_DATA);
parse_subscription_options(pstate, stmt->options, supported_opts, &opts);
/*
@@ -460,6 +474,7 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
values[Anum_pg_subscription_subenabled - 1] = BoolGetDatum(opts.enabled);
values[Anum_pg_subscription_subbinary - 1] = BoolGetDatum(opts.binary);
values[Anum_pg_subscription_substream - 1] = BoolGetDatum(opts.streaming);
+ values[Anum_pg_subscription_subonlylocaldata - 1] = BoolGetDatum(opts.onlylocal_data);
values[Anum_pg_subscription_subtwophasestate - 1] =
CharGetDatum(opts.twophase ?
LOGICALREP_TWOPHASE_STATE_PENDING :
@@ -565,7 +580,8 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
twophase_enabled = true;
walrcv_create_slot(wrconn, opts.slot_name, false, twophase_enabled,
- CRS_NOEXPORT_SNAPSHOT, NULL);
+ CRS_NOEXPORT_SNAPSHOT, NULL,
+ opts.onlylocal_data);
if (twophase_enabled)
UpdateTwoPhaseState(subid, LOGICALREP_TWOPHASE_STATE_ENABLED);
diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index 0d89db4e6a..326f60414e 100644
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -75,7 +75,8 @@ static char *libpqrcv_create_slot(WalReceiverConn *conn,
bool temporary,
bool two_phase,
CRSSnapshotAction snapshot_action,
- XLogRecPtr *lsn);
+ XLogRecPtr *lsn,
+ bool onlylocal_data);
static pid_t libpqrcv_get_backend_pid(WalReceiverConn *conn);
static WalRcvExecResult *libpqrcv_exec(WalReceiverConn *conn,
const char *query,
@@ -453,6 +454,10 @@ libpqrcv_startstreaming(WalReceiverConn *conn,
PQserverVersion(conn->streamConn) >= 150000)
appendStringInfoString(&cmd, ", two_phase 'on'");
+ if (options->proto.logical.onlylocal_data &&
+ PQserverVersion(conn->streamConn) >= 150000)
+ appendStringInfoString(&cmd, ", only_local 'on'");
+
pubnames = options->proto.logical.publication_names;
pubnames_str = stringlist_to_identifierstr(conn->streamConn, pubnames);
if (!pubnames_str)
@@ -869,7 +874,7 @@ libpqrcv_send(WalReceiverConn *conn, const char *buffer, int nbytes)
static char *
libpqrcv_create_slot(WalReceiverConn *conn, const char *slotname,
bool temporary, bool two_phase, CRSSnapshotAction snapshot_action,
- XLogRecPtr *lsn)
+ XLogRecPtr *lsn, bool onlylocal_data)
{
PGresult *res;
StringInfoData cmd;
@@ -899,6 +904,15 @@ libpqrcv_create_slot(WalReceiverConn *conn, const char *slotname,
appendStringInfoChar(&cmd, ' ');
}
+ if (onlylocal_data)
+ {
+ appendStringInfoString(&cmd, "ONLY_LOCAL");
+ if (use_new_options_syntax)
+ appendStringInfoString(&cmd, ", ");
+ else
+ appendStringInfoChar(&cmd, ' ');
+ }
+
if (use_new_options_syntax)
{
switch (snapshot_action)
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index 18cf931822..6305b93fc7 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -555,6 +555,15 @@ FilterByOrigin(LogicalDecodingContext *ctx, RepOriginId origin_id)
return filter_by_origin_cb_wrapper(ctx, origin_id);
}
+static inline bool
+FilterRemoteOriginData(LogicalDecodingContext *ctx, RepOriginId origin_id)
+{
+ if (ctx->callbacks.filter_remotedata_cb == NULL)
+ return false;
+
+ return filter_remotedata_cb_wrapper(ctx, origin_id);
+}
+
/*
* Handle rmgr LOGICALMSG_ID records for DecodeRecordIntoReorderBuffer().
*/
@@ -585,7 +594,8 @@ logicalmsg_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
message = (xl_logical_message *) XLogRecGetData(r);
if (message->dbId != ctx->slot->data.database ||
- FilterByOrigin(ctx, origin_id))
+ FilterByOrigin(ctx, origin_id) ||
+ FilterRemoteOriginData(ctx, origin_id))
return;
if (message->transactional &&
@@ -864,7 +874,8 @@ DecodeInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
return;
/* output plugin doesn't look for this origin, no need to queue */
- if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
+ if (FilterByOrigin(ctx, XLogRecGetOrigin(r)) ||
+ FilterRemoteOriginData(ctx, XLogRecGetOrigin(r)))
return;
change = ReorderBufferGetChange(ctx->reorder);
@@ -914,7 +925,8 @@ DecodeUpdate(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
return;
/* output plugin doesn't look for this origin, no need to queue */
- if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
+ if (FilterByOrigin(ctx, XLogRecGetOrigin(r)) ||
+ FilterRemoteOriginData(ctx, XLogRecGetOrigin(r)))
return;
change = ReorderBufferGetChange(ctx->reorder);
@@ -980,7 +992,8 @@ DecodeDelete(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
return;
/* output plugin doesn't look for this origin, no need to queue */
- if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
+ if (FilterByOrigin(ctx, XLogRecGetOrigin(r)) ||
+ FilterRemoteOriginData(ctx, XLogRecGetOrigin(r)))
return;
change = ReorderBufferGetChange(ctx->reorder);
@@ -1032,7 +1045,8 @@ DecodeTruncate(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
return;
/* output plugin doesn't look for this origin, no need to queue */
- if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
+ if (FilterByOrigin(ctx, XLogRecGetOrigin(r)) ||
+ FilterRemoteOriginData(ctx, XLogRecGetOrigin(r)))
return;
change = ReorderBufferGetChange(ctx->reorder);
@@ -1082,7 +1096,8 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
return;
/* output plugin doesn't look for this origin, no need to queue */
- if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
+ if (FilterByOrigin(ctx, XLogRecGetOrigin(r)) ||
+ FilterRemoteOriginData(ctx, XLogRecGetOrigin(r)))
return;
/*
@@ -1175,7 +1190,8 @@ DecodeSpecConfirm(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
return;
/* output plugin doesn't look for this origin, no need to queue */
- if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
+ if (FilterByOrigin(ctx, XLogRecGetOrigin(r)) ||
+ FilterRemoteOriginData(ctx, XLogRecGetOrigin(r)))
return;
change = ReorderBufferGetChange(ctx->reorder);
@@ -1250,7 +1266,8 @@ DecodeTXNNeedSkip(LogicalDecodingContext *ctx, XLogRecordBuffer *buf,
{
return (SnapBuildXactNeedsSkip(ctx->snapshot_builder, buf->origptr) ||
(txn_dbid != InvalidOid && txn_dbid != ctx->slot->data.database) ||
- ctx->fast_forward || FilterByOrigin(ctx, origin_id));
+ ctx->fast_forward || FilterByOrigin(ctx, origin_id) ||
+ FilterRemoteOriginData(ctx, origin_id));
}
/*
@@ -1335,7 +1352,8 @@ sequence_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
return;
/* output plugin doesn't look for this origin, no need to queue */
- if (FilterByOrigin(ctx, XLogRecGetOrigin(r)))
+ if (FilterByOrigin(ctx, XLogRecGetOrigin(r)) ||
+ FilterRemoteOriginData(ctx, XLogRecGetOrigin(r)))
return;
tupledata = XLogRecGetData(r);
diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c
index 934aa13f2d..19584eaea7 100644
--- a/src/backend/replication/logical/logical.c
+++ b/src/backend/replication/logical/logical.c
@@ -246,6 +246,8 @@ StartupDecodingContext(List *output_plugin_options,
(ctx->callbacks.stream_sequence_cb != NULL) ||
(ctx->callbacks.stream_truncate_cb != NULL);
+ ctx->onlylocal_data = ctx->callbacks.filter_remotedata_cb != NULL;
+
/*
* streaming callbacks
*
@@ -451,6 +453,8 @@ CreateInitDecodingContext(const char *plugin,
*/
ctx->twophase &= slot->data.two_phase;
+ ctx->onlylocal_data &= slot->data.onlylocal_data;
+
ctx->reorder->output_rewrites = ctx->options.receive_rewrites;
return ctx;
@@ -1178,6 +1182,37 @@ filter_by_origin_cb_wrapper(LogicalDecodingContext *ctx, RepOriginId origin_id)
return ret;
}
+bool
+filter_remotedata_cb_wrapper(LogicalDecodingContext *ctx,
+ RepOriginId origin_id)
+{
+ LogicalErrorCallbackState state;
+ ErrorContextCallback errcallback;
+ bool ret;
+
+ Assert(!ctx->fast_forward);
+
+ /* Push callback + info on the error context stack */
+ state.ctx = ctx;
+ state.callback_name = "filter_remoteorigin";
+ state.report_location = InvalidXLogRecPtr;
+ errcallback.callback = output_plugin_error_callback;
+ errcallback.arg = (void *) &state;
+ errcallback.previous = error_context_stack;
+ error_context_stack = &errcallback;
+
+ /* set output state */
+ ctx->accept_writes = false;
+
+ /* do the actual work: call callback */
+ ret = ctx->callbacks.filter_remotedata_cb(ctx, origin_id);
+
+ /* Pop the error context stack */
+ error_context_stack = errcallback.previous;
+
+ return ret;
+}
+
static void
message_cb_wrapper(ReorderBuffer *cache, ReorderBufferTXN *txn,
XLogRecPtr message_lsn, bool transactional,
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 1659964571..f5093ce8c9 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -1224,7 +1224,7 @@ LogicalRepSyncTableStart(XLogRecPtr *origin_startpos)
HOLD_INTERRUPTS();
walrcv_create_slot(LogRepWorkerWalRcvConn,
slotname, false /* permanent */ , false /* two_phase */ ,
- CRS_USE_SNAPSHOT, origin_startpos);
+ CRS_USE_SNAPSHOT, origin_startpos, false /* only_local */);
RESUME_INTERRUPTS();
/*
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 5d9acc6173..15385fb614 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -3575,6 +3575,7 @@ ApplyWorkerMain(Datum main_arg)
options.proto.logical.binary = MySubscription->binary;
options.proto.logical.streaming = MySubscription->stream;
options.proto.logical.twophase = false;
+ options.proto.logical.onlylocal_data = MySubscription->onlylocaldata;
if (!am_tablesync_worker())
{
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index ea57a0477f..0c9b60bd65 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -55,6 +55,8 @@ static void pgoutput_message(LogicalDecodingContext *ctx,
Size sz, const char *message);
static bool pgoutput_origin_filter(LogicalDecodingContext *ctx,
RepOriginId origin_id);
+static bool pgoutput_remoteorigin_filter(LogicalDecodingContext *ctx,
+ RepOriginId origin_id);
static void pgoutput_begin_prepare_txn(LogicalDecodingContext *ctx,
ReorderBufferTXN *txn);
static void pgoutput_prepare_txn(LogicalDecodingContext *ctx,
@@ -215,6 +217,7 @@ _PG_output_plugin_init(OutputPluginCallbacks *cb)
cb->commit_prepared_cb = pgoutput_commit_prepared_txn;
cb->rollback_prepared_cb = pgoutput_rollback_prepared_txn;
cb->filter_by_origin_cb = pgoutput_origin_filter;
+ cb->filter_remotedata_cb = pgoutput_remoteorigin_filter;
cb->shutdown_cb = pgoutput_shutdown;
/* transaction streaming */
@@ -239,11 +242,13 @@ parse_output_parameters(List *options, PGOutputData *data)
bool messages_option_given = false;
bool streaming_given = false;
bool two_phase_option_given = false;
+ bool onlylocal_data_given = false;
data->binary = false;
data->streaming = false;
data->messages = false;
data->two_phase = false;
+ data->onlylocal_data = false;
foreach(lc, options)
{
@@ -332,6 +337,16 @@ parse_output_parameters(List *options, PGOutputData *data)
data->two_phase = defGetBoolean(defel);
}
+ else if (strcmp(defel->defname, "only_local") == 0)
+ {
+ if (onlylocal_data_given)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("conflicting or redundant options")));
+ onlylocal_data_given = true;
+
+ data->onlylocal_data = defGetBoolean(defel);
+ }
else
elog(ERROR, "unrecognized pgoutput option: %s", defel->defname);
}
@@ -1450,6 +1465,16 @@ pgoutput_origin_filter(LogicalDecodingContext *ctx,
return false;
}
+static bool
+pgoutput_remoteorigin_filter(LogicalDecodingContext *ctx,
+ RepOriginId origin_id)
+{
+ PGOutputData *data = (PGOutputData *) ctx->output_plugin_private;
+
+ if (data->onlylocal_data && origin_id != InvalidRepOriginId)
+ return true;
+ return false;
+}
/*
* Shutdown the output plugin.
*
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 3d39fddaae..429bc1328c 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -253,7 +253,8 @@ ReplicationSlotValidateName(const char *name, int elevel)
*/
void
ReplicationSlotCreate(const char *name, bool db_specific,
- ReplicationSlotPersistency persistency, bool two_phase)
+ ReplicationSlotPersistency persistency, bool two_phase,
+ bool onlylocal_data)
{
ReplicationSlot *slot = NULL;
int i;
@@ -313,6 +314,7 @@ ReplicationSlotCreate(const char *name, bool db_specific,
slot->data.persistency = persistency;
slot->data.two_phase = two_phase;
slot->data.two_phase_at = InvalidXLogRecPtr;
+ slot->data.onlylocal_data = onlylocal_data;
/* and then data only present in shared memory */
slot->just_dirtied = false;
diff --git a/src/backend/replication/slotfuncs.c b/src/backend/replication/slotfuncs.c
index 886899afd2..0e0bc1e940 100644
--- a/src/backend/replication/slotfuncs.c
+++ b/src/backend/replication/slotfuncs.c
@@ -42,7 +42,8 @@ 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);
+ temporary ? RS_TEMPORARY : RS_PERSISTENT,
+ false, false);
if (immediately_reserve)
{
@@ -118,7 +119,8 @@ static void
create_logical_replication_slot(char *name, char *plugin,
bool temporary, bool two_phase,
XLogRecPtr restart_lsn,
- bool find_startpoint)
+ bool find_startpoint,
+ bool onlylocal_data)
{
LogicalDecodingContext *ctx = NULL;
@@ -133,7 +135,8 @@ create_logical_replication_slot(char *name, char *plugin,
* error as well.
*/
ReplicationSlotCreate(name, true,
- temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase);
+ temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase,
+ onlylocal_data);
/*
* Create logical decoding context to find start point or, if we don't
@@ -171,6 +174,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS)
Name plugin = PG_GETARG_NAME(1);
bool temporary = PG_GETARG_BOOL(2);
bool two_phase = PG_GETARG_BOOL(3);
+ bool onlylocal_data = PG_GETARG_BOOL(4);
Datum result;
TupleDesc tupdesc;
HeapTuple tuple;
@@ -189,7 +193,8 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS)
temporary,
two_phase,
InvalidXLogRecPtr,
- true);
+ true,
+ onlylocal_data);
values[0] = NameGetDatum(&MyReplicationSlot->data.name);
values[1] = LSNGetDatum(MyReplicationSlot->data.confirmed_flush);
@@ -231,7 +236,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS)
Datum
pg_get_replication_slots(PG_FUNCTION_ARGS)
{
-#define PG_GET_REPLICATION_SLOTS_COLS 14
+#define PG_GET_REPLICATION_SLOTS_COLS 15
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
@@ -429,6 +434,8 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
values[i++] = BoolGetDatum(slot_contents.data.two_phase);
+ values[i++] = BoolGetDatum(slot_contents.data.onlylocal_data);
+
Assert(i == PG_GET_REPLICATION_SLOTS_COLS);
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
@@ -794,6 +801,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot)
temporary,
false,
src_restart_lsn,
+ false,
false);
}
else
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index ceaff097b9..cfdefb1f22 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -374,7 +374,7 @@ WalReceiverMain(void)
"pg_walreceiver_%lld",
(long long int) walrcv_get_backend_pid(wrconn));
- walrcv_create_slot(wrconn, slotname, true, false, 0, NULL);
+ walrcv_create_slot(wrconn, slotname, true, false, 0, NULL, false);
SpinLockAcquire(&walrcv->mutex);
strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 5a718b1fe9..b826326b98 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -963,12 +963,14 @@ static void
parseCreateReplSlotOptions(CreateReplicationSlotCmd *cmd,
bool *reserve_wal,
CRSSnapshotAction *snapshot_action,
- bool *two_phase)
+ bool *two_phase,
+ bool *onlylocal_data)
{
ListCell *lc;
bool snapshot_action_given = false;
bool reserve_wal_given = false;
bool two_phase_given = false;
+ bool onlylocal_data_given = false;
/* Parse options */
foreach(lc, cmd->options)
@@ -1019,6 +1021,15 @@ parseCreateReplSlotOptions(CreateReplicationSlotCmd *cmd,
two_phase_given = true;
*two_phase = defGetBoolean(defel);
}
+ else if (strcmp(defel->defname, "only_local") == 0)
+ {
+ if (onlylocal_data_given || cmd->kind != REPLICATION_KIND_LOGICAL)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("conflicting or redundant options")));
+ onlylocal_data_given = true;
+ *onlylocal_data = defGetBoolean(defel);
+ }
else
elog(ERROR, "unrecognized option: %s", defel->defname);
}
@@ -1035,6 +1046,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
char *slot_name;
bool reserve_wal = false;
bool two_phase = false;
+ bool onlylocal_data = false;
CRSSnapshotAction snapshot_action = CRS_EXPORT_SNAPSHOT;
DestReceiver *dest;
TupOutputState *tstate;
@@ -1044,13 +1056,14 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
Assert(!MyReplicationSlot);
- parseCreateReplSlotOptions(cmd, &reserve_wal, &snapshot_action, &two_phase);
+ parseCreateReplSlotOptions(cmd, &reserve_wal, &snapshot_action, &two_phase,
+ &onlylocal_data);
if (cmd->kind == REPLICATION_KIND_PHYSICAL)
{
ReplicationSlotCreate(cmd->slotname, false,
cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT,
- false);
+ false, false);
}
else
{
@@ -1065,7 +1078,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
*/
ReplicationSlotCreate(cmd->slotname, true,
cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL,
- two_phase);
+ two_phase, onlylocal_data);
}
if (cmd->kind == REPLICATION_KIND_LOGICAL)
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 6957567264..d7a4e24167 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -3104,7 +3104,7 @@ psql_completion(const char *text, int start, int end)
else if (HeadMatches("CREATE", "SUBSCRIPTION") && TailMatches("WITH", "("))
COMPLETE_WITH("binary", "connect", "copy_data", "create_slot",
"enabled", "slot_name", "streaming",
- "synchronous_commit", "two_phase");
+ "synchronous_commit", "two_phase", "only_local");
/* CREATE TRIGGER --- is allowed inside CREATE SCHEMA, so use TailMatches */
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 7f1ee97f55..e002563a2a 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -10782,9 +10782,9 @@
proname => 'pg_get_replication_slots', prorows => '10', proisstrict => 'f',
proretset => 't', provolatile => 's', prorettype => 'record',
proargtypes => '',
- proallargtypes => '{name,name,text,oid,bool,bool,int4,xid,xid,pg_lsn,pg_lsn,text,int8,bool}',
- proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
- proargnames => '{slot_name,plugin,slot_type,datoid,temporary,active,active_pid,xmin,catalog_xmin,restart_lsn,confirmed_flush_lsn,wal_status,safe_wal_size,two_phase}',
+ proallargtypes => '{name,name,text,oid,bool,bool,int4,xid,xid,pg_lsn,pg_lsn,text,int8,bool,bool}',
+ proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+ proargnames => '{slot_name,plugin,slot_type,datoid,temporary,active,active_pid,xmin,catalog_xmin,restart_lsn,confirmed_flush_lsn,wal_status,safe_wal_size,two_phase,only_local}',
prosrc => 'pg_get_replication_slots' },
{ oid => '3786', descr => 'set up a logical replication slot',
proname => 'pg_create_logical_replication_slot', provolatile => 'v',
diff --git a/src/include/catalog/pg_subscription.h b/src/include/catalog/pg_subscription.h
index 18c291289f..6e3119247c 100644
--- a/src/include/catalog/pg_subscription.h
+++ b/src/include/catalog/pg_subscription.h
@@ -65,6 +65,8 @@ CATALOG(pg_subscription,6100,SubscriptionRelationId) BKI_SHARED_RELATION BKI_ROW
bool substream; /* Stream in-progress transactions. */
+ bool subonlylocaldata; /* skip copying of remote origin data */
+
char subtwophasestate; /* Stream two-phase transactions */
#ifdef CATALOG_VARLEN /* variable-length fields start here */
@@ -102,6 +104,7 @@ typedef struct Subscription
bool binary; /* Indicates if the subscription wants data in
* binary format */
bool stream; /* Allow streaming in-progress transactions. */
+ bool onlylocaldata; /* Skip copying of remote orging data */
char twophasestate; /* Allow streaming two-phase transactions */
char *conninfo; /* Connection string to the publisher */
char *slotname; /* Name of the replication slot */
diff --git a/src/include/replication/logical.h b/src/include/replication/logical.h
index 1097cc9799..82014fe252 100644
--- a/src/include/replication/logical.h
+++ b/src/include/replication/logical.h
@@ -99,6 +99,8 @@ typedef struct LogicalDecodingContext
*/
bool twophase_opt_given;
+ bool onlylocal_data;
+
/*
* State for writing output.
*/
@@ -138,6 +140,8 @@ extern void LogicalConfirmReceivedLocation(XLogRecPtr lsn);
extern bool filter_prepare_cb_wrapper(LogicalDecodingContext *ctx,
TransactionId xid, const char *gid);
extern bool filter_by_origin_cb_wrapper(LogicalDecodingContext *ctx, RepOriginId origin_id);
+extern bool filter_remotedata_cb_wrapper(LogicalDecodingContext *ctx,
+ RepOriginId origin_id);
extern void ResetLogicalStreamingState(void);
extern void UpdateDecodingStats(LogicalDecodingContext *ctx);
diff --git a/src/include/replication/output_plugin.h b/src/include/replication/output_plugin.h
index a16bebf76c..52b5de3eb8 100644
--- a/src/include/replication/output_plugin.h
+++ b/src/include/replication/output_plugin.h
@@ -106,6 +106,12 @@ typedef void (*LogicalDecodeSequenceCB) (struct LogicalDecodingContext *ctx,
typedef bool (*LogicalDecodeFilterByOriginCB) (struct LogicalDecodingContext *ctx,
RepOriginId origin_id);
+/*
+ * Filter remote origin changes.
+ */
+typedef bool (*LogicalDecodeFilterRemoteOriginCB) (struct LogicalDecodingContext *ctx,
+ RepOriginId origin_id);
+
/*
* Called to shutdown an output plugin.
*/
@@ -246,6 +252,7 @@ typedef struct OutputPluginCallbacks
LogicalDecodeMessageCB message_cb;
LogicalDecodeSequenceCB sequence_cb;
LogicalDecodeFilterByOriginCB filter_by_origin_cb;
+ LogicalDecodeFilterRemoteOriginCB filter_remotedata_cb;
LogicalDecodeShutdownCB shutdown_cb;
/* streaming of changes at prepare time */
diff --git a/src/include/replication/pgoutput.h b/src/include/replication/pgoutput.h
index eafedd610a..e8fac6b3f8 100644
--- a/src/include/replication/pgoutput.h
+++ b/src/include/replication/pgoutput.h
@@ -29,6 +29,7 @@ typedef struct PGOutputData
bool streaming;
bool messages;
bool two_phase;
+ bool onlylocal_data;
} PGOutputData;
#endif /* PGOUTPUT_H */
diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h
index 24b30210c3..833d380b0f 100644
--- a/src/include/replication/slot.h
+++ b/src/include/replication/slot.h
@@ -94,6 +94,8 @@ typedef struct ReplicationSlotPersistentData
*/
bool two_phase;
+ bool onlylocal_data;
+
/* plugin name */
NameData plugin;
} ReplicationSlotPersistentData;
@@ -195,7 +197,8 @@ extern void ReplicationSlotsShmemInit(void);
/* management of individual slots */
extern void ReplicationSlotCreate(const char *name, bool db_specific,
- ReplicationSlotPersistency p, bool two_phase);
+ ReplicationSlotPersistency p, bool two_phase,
+ bool onlylocal_data);
extern void ReplicationSlotPersist(void);
extern void ReplicationSlotDrop(const char *name, bool nowait);
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index 92f73a55b8..e62dca9b45 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -183,6 +183,7 @@ typedef struct
bool streaming; /* Streaming of large transactions */
bool twophase; /* Streaming of two-phase transactions at
* prepare time */
+ bool onlylocal_data;
} logical;
} proto;
} WalRcvStreamOptions;
@@ -351,7 +352,8 @@ typedef char *(*walrcv_create_slot_fn) (WalReceiverConn *conn,
bool temporary,
bool two_phase,
CRSSnapshotAction snapshot_action,
- XLogRecPtr *lsn);
+ XLogRecPtr *lsn,
+ bool onlylocal_data);
/*
* walrcv_get_backend_pid_fn
@@ -423,8 +425,8 @@ extern PGDLLIMPORT WalReceiverFunctionsType *WalReceiverFunctions;
WalReceiverFunctions->walrcv_receive(conn, buffer, wait_fd)
#define walrcv_send(conn, buffer, nbytes) \
WalReceiverFunctions->walrcv_send(conn, buffer, nbytes)
-#define walrcv_create_slot(conn, slotname, temporary, two_phase, snapshot_action, lsn) \
- WalReceiverFunctions->walrcv_create_slot(conn, slotname, temporary, two_phase, snapshot_action, lsn)
+#define walrcv_create_slot(conn, slotname, temporary, two_phase, snapshot_action, lsn, onlylocal_data) \
+ WalReceiverFunctions->walrcv_create_slot(conn, slotname, temporary, two_phase, snapshot_action, lsn, onlylocal_data)
#define walrcv_get_backend_pid(conn) \
WalReceiverFunctions->walrcv_get_backend_pid(conn)
#define walrcv_exec(conn, exec, nRetTypes, retTypes) \
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 1420288d67..dc677e5c67 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1456,8 +1456,9 @@ pg_replication_slots| SELECT l.slot_name,
l.confirmed_flush_lsn,
l.wal_status,
l.safe_wal_size,
- l.two_phase
- FROM (pg_get_replication_slots() l(slot_name, plugin, slot_type, datoid, temporary, active, active_pid, xmin, catalog_xmin, restart_lsn, confirmed_flush_lsn, wal_status, safe_wal_size, two_phase)
+ l.two_phase,
+ l.only_local
+ FROM (pg_get_replication_slots() l(slot_name, plugin, slot_type, datoid, temporary, active, active_pid, xmin, catalog_xmin, restart_lsn, confirmed_flush_lsn, wal_status, safe_wal_size, two_phase, only_local)
LEFT JOIN pg_database d ON ((l.datoid = d.oid)));
pg_roles| SELECT pg_authid.rolname,
pg_authid.rolsuper,
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index c6b302c7b2..0bf093858b 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1370,6 +1370,7 @@ LogicalDecodeCommitCB
LogicalDecodeCommitPreparedCB
LogicalDecodeFilterByOriginCB
LogicalDecodeFilterPrepareCB
+LogicalDecodeFilterRemoteOriginCB
LogicalDecodeMessageCB
LogicalDecodePrepareCB
LogicalDecodeRollbackPreparedCB
--
2.30.2
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Handle infinite recursion in logical replication setup
2022-02-23 06:29 Handle infinite recursion in logical replication setup vignesh C <[email protected]>
@ 2022-04-05 02:47 ` Peter Smith <[email protected]>
2022-04-05 06:15 ` Re: Handle infinite recursion in logical replication setup Amit Kapila <[email protected]>
0 siblings, 1 reply; 4+ messages in thread
From: Peter Smith @ 2022-04-05 02:47 UTC (permalink / raw)
To: vignesh C <[email protected]>; +Cc: PostgreSQL Hackers <[email protected]>
Here are my comments for the latest patch v6-0002.
PATCH v6-0002 comments
======================
2.1 General - should this be an independent patch?
In many ways, I think most of this patch is unrelated to the other
"local_only" patch (v6-0001).
For example, IIUC even in the current HEAD, we could consider it to be
a user error if multiple SUBSCRIPTIONS or multiple PUBLICATIONS of the
same SUBSCRIPTION are replicating to the same TABLE on the same node
and using "copy_data = on".
So I think it would be ok to throw an ERROR if such a copy_data clash
is detected, and then the user will have to change to use "copy_data =
off" for some/all of them to avoid data duplication.
The "local_only" option only adds some small logic to this new ERROR,
but it's not really a prerequisite at all.
e.g. this whole ERROR part of the patch can be a separate thread.
~~~
2.2 General - can we remove the "force" enum?
Now, because I consider the clashing "copy_data = on" ERROR to be a
user error, I think that is something that the user can already take
care of themselves just using the copy_data = off.
I did not really like the modifying of the "copy_data" option from
just boolean to some kind of hybrid boolean + "force".
a) It smells a bit off to me. IMO replication is supposed to end up
with the same (replicated) data on the standby machine but this
"force" mode seems to be just helping the user to break that concept
and say - "I know what I'm doing, and I don't care if I get lots of
duplicated data in the replica table - just let me do it"...
b) It also somehow feels like the new "force" was introduced mostly to
make the code ERROR handling implementation simpler, rather than to
make the life of the end-user better. Yes, if force is removed maybe
the copy-clash-detection-code will need to be internally quite more
complex than it is now, but that is how it should be, instead of
putting extra burden on the user (e.g. by complicating the PG docs and
giving them yet more alternatives to configure). I think any clashing
copy_data options really is a user error, but also I think the current
boolean copy_data true/false already gives the user a way to fix it.
c) Actually, your new error hint messages are similar to my
perspective: They already say "Use CREATE/ALTER SUBSCRIPTION with
copy_data = off or force". All I am saying is remove the "force", and
the user can still fix the problem just by using "copy_data = off"
appropriately.
======
So (from above) I am not much in favour of the copy_data becoming a
hybrid enum and using "force", yet that is what most of this patch is
implementing. Anyway, the remainder of my review comments here are for
the code in its current form. Maybe if "force" can be removed most of
the following comments end up being redundant.
======
2.3 Commit message - wording
This message is difficult to understand.
I think that the long sentence "Now when user is trying..." can be
broken into more manageable parts.
This part "and throw an error so that user can handle the initial copy
data." also seemed a bit vague.
~~~
2.4 Commit message - more functions
"This patch does couple of things:"
IIUC, there seems a third thing implemented by this patch but not
described by the comment. I think it also adds support for ALTER
SUBSCRIPTION SET PUBLICATION WITH (subscribe_local_only)
~~~
2.5 doc/src/sgml/ref/create_subscription.sgml - wording
@@ -161,6 +161,13 @@ CREATE SUBSCRIPTION <replaceable
class="parameter">subscription_name</replaceabl
the replicated changes that was generated from other nodes. The
default is <literal>false</literal>.
</para>
+ <para>
+ If the tables in the publication were also subscribing to the data in
+ the publisher from other publishers, it will affect the
+ <command>CREATE SUBSCRIPTION</command> based on the value specified
+ for <literal>copy_data</literal> option. Refer to the
+ <xref linkend="sql-createsubscription-notes" /> for details.
+ </para>
Is there is a simpler way to express all that?
SUGGESTION
There is some interation between the option "subscribe_local_only" and
option "copy_data". Refer to the <xref
linkend="sql-createsubscription-notes" /> for details.
~~~
2.6 doc/src/sgml/ref/create_subscription.sgml - whitespace
@@ -213,18 +220,28 @@ CREATE SUBSCRIPTION <replaceable
class="parameter">subscription_name</replaceabl
</varlistentry>
<varlistentry>
- <term><literal>copy_data</literal> (<type>boolean</type>)</term>
+ <term><literal>copy_data</literal> (<type>enum</type>)</term>
<listitem>
<para>
Specifies whether to copy pre-existing data in the publications
- that are being subscribed to when the replication starts.
- The default is <literal>true</literal>.
+ that are being subscribed to when the replication starts. This
+ parameter may be either <literal>true</literal>,
+ <literal>false</literal> or <literal>force</literal>. The default is
+ <literal>true</literal>.
That last line has trailing whitespace.
~~~
2.7 doc/src/sgml/ref/create_subscription.sgml - wording
+ <para>
+ If the tables in the publication were also subscribing to the data in
+ the publisher from other publishers, it will affect the
+ <command>CREATE SUBSCRIPTION</command> based on the value specified
+ for <literal>subscribe_local_only</literal> option. Refer to the
+ <xref linkend="sql-createsubscription-notes" /> for details.
+ </para>
This is similar to review comment #2.5 which I thought could be
written in a simpler way.
~~~
2.8 doc/src/sgml/ref/create_subscription.sgml
@@ -375,6 +392,42 @@ CREATE SUBSCRIPTION <replaceable
class="parameter">subscription_name</replaceabl
can have non-existent publications.
</para>
+ <para>
+ Let's consider an existing Multi master logical replication setup between
+ Node1 and Node2 that is created using the following steps:
+ a) Node1 - Publication publishing employee table.
+ b) Node2 - Subscription subscribing from publication pub1 with
+ <literal>subscribe_local_only</literal>.
+ c) Node2 - Publication publishing employee table.
+ d) Node1 - Subscription subscribing from publication pub2 with
+ <literal>subscribe_local_only</literal>.
+ Now when user is trying to add another node Node3 to the above Multi master
+ logical replication setup, user will have to create one subscription
+ subscribing from Node1 and another subscription subscribing from Node2 in
+ Node3 using <literal>subscribe_local_only</literal> option and
+ <literal>copy_data</literal> as <literal>true</literal>, while
+ the subscription is created, server will identify that Node2 is subscribing
+ from Node1 and Node1 is subscribing from Node2 and throw an error like:
+ <programlisting>
+postgres=# CREATE SUBSCRIPTION mysub CONNECTION 'host=192.168.1.50
port=5432 user=foo dbname=foodb'
+ PUBLICATION mypublication, insert_only with
(subscribe_local_only=on);
+ERROR: CREATE/ALTER SUBSCRIPTION with subscribe_local_only and
copy_data as true is not allowed when the publisher might have
replicated data, table:public.t1 might have replicated data in the
publisher
+HINT: Use CREATE/ALTER SUBSCRIPTION with copy_data = off or force
+ </programlisting>
+ In this scenario user can solve this based on one of the 2 possibilities,
+ a) If there are no data present in Node1 and Node2, then the user can create
+ the subscriptions to Node1 and Node2 with
+ <literal>subscribe_local_only</literal> as <literal>true</literal> and
+ <literal>copy_data</literal> as <literal>false</literal>. b) If the data is
+ present, then the user can create subscription with
+ <literal>copy_data</literal> as <literal>force</literal> on Node1 and
+ <literal>copy_data</literal> as <literal>false</literal> on Node2, before
+ allowing any operations on the respective tables of Node1 and Node2, in this
+ case <literal>copy_data</literal> is <literal>false</literal> on Node2
+ because the data will be replicated to each other and available on both the
+ nodes.
+ </para>
+
That is a large slab of text in the Notes, so not very easy to digest it.
I'm not sure what to suggest for this -
- Perhaps the a,b,c,d should all be "lists" so it renders differently?
- It almost seems like too much information to be included in this
"Notes" section, Maybe it needs its own full page in PG Docs "Logical
Replication" to discuss this topic.
~~~
2.9 src/backend/commands/subscriptioncmds.c - IS_COPY_DATA_VALID
@@ -69,6 +69,18 @@
/* check if the 'val' has 'bits' set */
#define IsSet(val, bits) (((val) & (bits)) == (bits))
+#define IS_COPY_DATA_VALID(copy_data) (copy_data != COPY_DATA_OFF)
The macro seems misnamed because "off" is also "valid". It seems like
it should be called something different like IS_COPY_DATA, or
IS_COPY_DATA_ON_OR_FORCE, etc.
~~~
2.10 src/backend/commands/subscriptioncmds.c - DefGetCopyData
+ /*
+ * The set of strings accepted here should match up with
+ * the grammar's opt_boolean_or_string production.
+ */
+ if (pg_strcasecmp(sval, "true") == 0)
+ return COPY_DATA_ON;
+ if (pg_strcasecmp(sval, "false") == 0)
+ return COPY_DATA_OFF;
+ if (pg_strcasecmp(sval, "on") == 0)
+ return COPY_DATA_ON;
+ if (pg_strcasecmp(sval, "off") == 0)
+ return COPY_DATA_OFF;
+ if (pg_strcasecmp(sval, "force") == 0)
+ return COPY_DATA_FORCE;
Maybe combine the return for true/on and false/off?
~~~
2.11 src/backend/commands/subscriptioncmds.c - fetch_table_list
+ appendStringInfoString(&cmd,
+ "SELECT DISTINCT N.nspname AS schemaname, C.relname AS tablename,
PS.srsubstate as replicated\n"
+ "FROM pg_publication P,\n"
+ "LATERAL pg_get_publication_tables(P.pubname) GPT\n"
+ "LEFT JOIN pg_subscription_rel PS ON (GPT.relid = PS.srrelid),\n"
+ "pg_class C JOIN pg_namespace N ON (N.oid = C.relnamespace)\n"
+ "WHERE C.oid = GPT.relid AND P.pubname in (");
+
That blank line is not needed (it was not there previously) because
the next get_publications_str is a continuation of this SQL.
~~~
2.12 src/backend/commands/subscriptioncmds.c - fetch_table_list comment
+ * It is quite possible that subscriber has not yet pulled data to
+ * the tables, but in ideal cases the table data will be subscribed.
+ * Too keep the code simple it is not checked if the subscriber table
+ * has pulled the data or not.
+ */
Typo "Too" -> "To"
~~~
2.13 src/backend/commands/subscriptioncmds.c - force
+ if (copydata == COPY_DATA_ON && only_local && !slot_attisnull(slot, 3))
+ ereport(ERROR,
+ errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("CREATE/ALTER SUBSCRIPTION with subscribe_local_only and
copy_data as true is not allowed when the publisher might have
replicated data, table:%s.%s might have replicated data in the
publisher",
+ nspname, relname),
+ errhint("Use CREATE/ALTER SUBSCRIPTION with copy_data = off or force"));
AFAIK this is the only code of this patch that is distinguishing
between "force" and the "on". As I wrote at the beginning of this post
I feel you can keep this ERROR (maybe the way to detect it needs to be
more complex) and the user can fix it just by using "copy_data = off"
appropriately. So then copy_data does not need to be changed.
~~~
2.14 src/test/regress/sql/subscription.sql - missing tests
The new copy_data is not really an enum true/false/force like the PG
docs claims.
It seems more like some kind of hybrid boolean+force. So if that is
how it is going to be then there are missing test cases to make sure
that values like "on"/"off"/"0"/"1" still are working.
~~~
2.15 src/test/subscription/t/032_circular.pl
@@ -65,6 +69,25 @@ $node_A->safe_psql('postgres', "
PUBLICATION tap_pub_B
WITH (subscribe_local_only = on, copy_data = off)");
+($result, $stdout, $stderr) = $node_A->psql('postgres', "
+ CREATE SUBSCRIPTION tap_sub_A1
+ CONNECTION '$node_B_connstr application_name=$appname_A'
+ PUBLICATION tap_pub_B
+ WITH (subscribe_local_only = on, copy_data = on)");
+like(
+ $stderr,
+ qr/ERROR: CREATE\/ALTER SUBSCRIPTION with
subscribe_local_only and copy_data as true is not allowed when the
publisher might have replicated data/,
+ "Create subscription with subscribe_local_only and copy_data
having replicated table in publisher");
+
+$node_A->safe_psql('postgres', "
+ CREATE SUBSCRIPTION tap_sub_A2
+ CONNECTION '$node_B_connstr application_name=$appname_A'
+ PUBLICATION tap_pub_B
+ WITH (subscribe_local_only = on, copy_data = force)");
+
+$node_A->safe_psql('postgres', "
+ DROP SUBSCRIPTION tap_sub_A2");
+
Maybe underneath it is the same, but from the outside, this looks like
a slightly different scenario from what is mentioned everywhere else
in the patch.
I think it would be better to create a new Node_C (aka Node3) so then
the TAP test can use the same example that you give in the commit
message and the PG docs notes.
------
Kind Regards,
Peter Smith.
Fujitsu Australia
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Handle infinite recursion in logical replication setup
2022-02-23 06:29 Handle infinite recursion in logical replication setup vignesh C <[email protected]>
2022-04-05 02:47 ` Re: Handle infinite recursion in logical replication setup Peter Smith <[email protected]>
@ 2022-04-05 06:15 ` Amit Kapila <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Amit Kapila @ 2022-04-05 06:15 UTC (permalink / raw)
To: Peter Smith <[email protected]>; +Cc: vignesh C <[email protected]>; PostgreSQL Hackers <[email protected]>
On Tue, Apr 5, 2022 at 8:17 AM Peter Smith <[email protected]> wrote:
>
> Here are my comments for the latest patch v6-0002.
>
> PATCH v6-0002 comments
> ======================
>
> 2.1 General - should this be an independent patch?
>
I think both the patches are dependent and might get committed
together if the concept proved to be useful and doesn't have flaws.
> In many ways, I think most of this patch is unrelated to the other
> "local_only" patch (v6-0001).
>
> For example, IIUC even in the current HEAD, we could consider it to be
> a user error if multiple SUBSCRIPTIONS or multiple PUBLICATIONS of the
> same SUBSCRIPTION are replicating to the same TABLE on the same node
> and using "copy_data = on".
>
> So I think it would be ok to throw an ERROR if such a copy_data clash
> is detected, and then the user will have to change to use "copy_data =
> off" for some/all of them to avoid data duplication.
>
> The "local_only" option only adds some small logic to this new ERROR,
> but it's not really a prerequisite at all.
>
> e.g. this whole ERROR part of the patch can be a separate thread.
>
> ~~~
>
> 2.2 General - can we remove the "force" enum?
>
> Now, because I consider the clashing "copy_data = on" ERROR to be a
> user error, I think that is something that the user can already take
> care of themselves just using the copy_data = off.
>
> I did not really like the modifying of the "copy_data" option from
> just boolean to some kind of hybrid boolean + "force".
>
> a) It smells a bit off to me. IMO replication is supposed to end up
> with the same (replicated) data on the standby machine but this
> "force" mode seems to be just helping the user to break that concept
> and say - "I know what I'm doing, and I don't care if I get lots of
> duplicated data in the replica table - just let me do it"...
>
> b) It also somehow feels like the new "force" was introduced mostly to
> make the code ERROR handling implementation simpler, rather than to
> make the life of the end-user better. Yes, if force is removed maybe
> the copy-clash-detection-code will need to be internally quite more
> complex than it is now, but that is how it should be, instead of
> putting extra burden on the user (e.g. by complicating the PG docs and
> giving them yet more alternatives to configure). I think any clashing
> copy_data options really is a user error, but also I think the current
> boolean copy_data true/false already gives the user a way to fix it.
>
> c) Actually, your new error hint messages are similar to my
> perspective: They already say "Use CREATE/ALTER SUBSCRIPTION with
> copy_data = off or force". All I am saying is remove the "force", and
> the user can still fix the problem just by using "copy_data = off"
> appropriately.
>
How will it work if there is more than one table? copy_data = "off"
means it won't copy any of the other tables in the corresponding
publication(s). I think it is primarily to give the user some option
where she understands the logical replication setup better and
understands that this won't be a problem.
--
With Regards,
Amit Kapila.
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2022-04-05 06:15 UTC | newest]
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-- links below jump to the message on this page --
2020-12-03 15:19 [PATCH 3/3] Extended statistics on expressions Tomas Vondra <[email protected]>
2022-02-23 06:29 Handle infinite recursion in logical replication setup vignesh C <[email protected]>
2022-04-05 02:47 ` Re: Handle infinite recursion in logical replication setup Peter Smith <[email protected]>
2022-04-05 06:15 ` Re: Handle infinite recursion in logical replication setup Amit Kapila <[email protected]>
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